JP2023125315A - Base station, communication system, and communication method - Google Patents

Abstract

To provide a base station, a communication system, and a communication method that can suppress reduction in throughput.SOLUTION: A base station includes: a use channel information acquisition unit 114 that acquires first use channel information transmitted from another base station and indicating a first use channel used for transmitting and receiving data frames with the other base station; a use channel determination unit 115 that determines that a channel belonging to any one frequency band W52, W53, or W56, different from the first use channel, among the frequency bands W52, W53, and W56 is a second use channel used for transmitting and receiving data frames with the other base station; and a use channel notification unit 116 that transmits the use channel information indicating the determined use channel to the other base station.SELECTED DRAWING: Figure 3

Description

The present invention relates to a base station, a communication system, and a communication method.

A wireless communication system has been proposed that includes a plurality of wireless base stations that can communicate with each other using WDS (Wireless Distribution System) communication that transmits and receives data between multiple wireless base stations by wireless communication (for example, Patent Document 1 reference). In addition, in this wireless communication system, when communicating in Japan using a channel belonging to channel group W56 among channels in the 5 GHz band, if radar waves are detected, the channel in use is stopped and other channels are used. The radio base station that detects radar waves notifies other radio base stations performing WDS communication of the channel to be used for communication.

JP 2017-200156 Publication

However, in the wireless communication system that performs WDS communication described in Patent Document 1, if the timings of transmitting frames at multiple wireless base stations overlap, there is a risk that throughput may decrease due to insufficient bandwidth. For example, there is a case where multiple handsets under a wireless base station perform WDS communication at the same transmission timing. In WDS communication, multiple wireless base stations communicate with each other using the same channel (the same channel), so one band is used by the communication of multiple handsets due to the communication of the handset. As a result, throughput decreases due to a lack of bandwidth in the wireless communication system.

The present invention has been made in view of the above, and an object of the present invention is to provide a base station, a communication system, and a communication method that can suppress a decrease in throughput.

In order to achieve the above object, the base station according to the present invention includes:
a plurality of wireless modules that wirelessly communicate with a plurality of other base stations through channels belonging to one of a plurality of frequency bands;
First used channel information indicating a first used channel used for transmitting and receiving data frames to and from the first base station, which is transmitted from a preset first base station among the other plurality of base stations. a usage channel information acquisition unit that acquires the
A channel different from the first used channel is used as a second used channel used for transmitting and receiving data frames with a second base station different from the first base station among the other plurality of base stations. a usage channel determination unit that determines;
and a channel-in-use notification unit that transmits second channel information indicating the determined second channel in use to the second base station via any one of the plurality of wireless modules.

The communication system according to the present invention seen from another point of view is as follows:
comprising a first base station, a second base station, and a third base station capable of communicating with the first base station and the second base station,
The first base station, the second base station, and the third base station each have:
a plurality of wireless modules that wirelessly communicate using channels belonging to one of a plurality of mutually different frequency bands;
The third base station is
a used channel information acquisition unit that acquires first used channel information indicating a first used channel used for transmitting and receiving data frames to and from the first base station transmitted from the first base station;
a usage channel determining unit that determines a channel different from the first usage channel as a second usage channel used for transmitting and receiving data frames to and from the second base station;
a used channel notification unit that transmits second used channel information indicating the determined second used channel to the second base station via any one of the plurality of wireless modules.

The communication method according to the present invention from another perspective is as follows:
A communication method using a plurality of wireless modules that wirelessly communicate with a plurality of other base stations using channels belonging to one of a plurality of mutually different frequency bands,
First used channel information indicating a first used channel used for transmitting and receiving data frames to and from the first base station, which is transmitted from a preset first base station among the other plurality of base stations. and the steps to obtain
A channel different from the first used channel is used as a second used channel used for transmitting and receiving data frames with a second base station different from the first base station among the other plurality of base stations. Steps to decide;
transmitting second usage channel information indicating the determined second usage channel to the second base station via any one of the plurality of wireless modules.

According to the base station according to the present invention, the usage channel determination section uses a channel belonging to a frequency band different from the first usage channel to use the second usage channel for transmitting and receiving data frames to and from the second base station. decided on. As a result, the first channel used for transmitting and receiving data frames with the first base station and the second channel used for transmitting and receiving data frames with the second base station are different from each other. Therefore, when transmitting a data frame from a slave unit under its own base station to a slave unit under the first base station or second base station, it becomes easier to secure the bandwidth required for wireless communication between base stations. . Therefore, it is possible to suppress a decrease in throughput in data frame transmission due to a shortage of bandwidth that occurs in conventional WDS communication in which wireless communication between base stations is performed using one channel.

1 is a diagram showing the configuration of a communication system according to Embodiment 1 of the present invention. 1 is a diagram showing a hardware configuration of a base station according to Embodiment 1. FIG. 1 is a diagram showing a functional configuration of a base station according to Embodiment 1. FIG. (A) is a diagram showing an example of information stored in the usage status storage unit according to Embodiment 1, and (B) is a diagram showing an example of information stored in the usage channel storage unit according to Embodiment 1. be. FIG. 2 is a sequence diagram showing the operation of the communication system according to the first embodiment. FIG. 2 is a sequence diagram showing the operation of the communication system according to the first embodiment. 3 is a flowchart illustrating an example of the flow of communication control processing executed by the upper base station according to the first embodiment. 3 is a flowchart illustrating an example of the flow of a usage channel determination process executed by an upper base station according to Embodiment 1. FIG. 5 is a flowchart illustrating an example of the flow of communication control processing executed by a lower base station according to Embodiment 1. FIG. FIG. 2 is a diagram showing the functional configuration of a base station according to Embodiment 2 of the present invention. FIG. 6 is a diagram illustrating an example of information stored in a used channel storage unit according to Embodiment 2; FIG. 2 is a sequence diagram showing the operation of the communication system according to Embodiment 2. FIG. 7 is a flowchart illustrating an example of a flow of communication control processing executed by a base station according to Embodiment 2. FIG. It is a diagram showing the configuration of a communication system according to a modification.

(Embodiment 1)
Hereinafter, a base station according to an embodiment of the present invention will be described in detail with reference to the drawings. The base station according to this embodiment includes a plurality of wireless modules that wirelessly communicate with a plurality of other base stations using channels belonging to one of a plurality of mutually different frequency bands. The base station then receives first usage status information indicating the usage status of each of the plurality of frequency bands of the base station, and one frequency band used for transmitting and receiving data frames between the base station and the first base station set in advance. and a second usage status indicating the usage status of each of the plurality of frequency bands at a second base station different from the first base station among the other plurality of base stations. Based on the information, a channel different from the first used channel is determined as the second used channel used for transmitting and receiving data frames to and from the second base station. This embodiment will be described in detail below.

For example, as shown in FIG. 1, the communication system according to the present embodiment includes three base stations 1 (1A, 1B, 1C) and terminal devices 3 (3A, 3B, 3C) under each base station 1. , 3D, 3E, 3F). This communication system constructs a wireless LAN network using a WDS (Wireless Distribution System) function. The base station is, for example, an access point employed in a home network or an in-office wireless LAN. A hierarchical relationship is set between the three base stations 1A, 1B, and 1C. For example, base station 1A is at the top, base station 1A is above base station 1B, and base station 1B is above base station 1C. It is set. In this case, the base stations 1A, 1B, and 1C correspond to the first base station, third base station, and second base station described in the claims, respectively. The terminal device 3 is, for example, a general-purpose personal computer equipped with a wireless module.

As shown in FIG. 2, each base station 1 according to the present embodiment includes a CPU (Central Processing Unit) 101, a main storage section 102, an auxiliary storage section 103, and three wireless modules 105A, 105B, and 105C. , and a bus 109 that connects each part. The main storage unit 102 is composed of volatile memory such as RAM (Random Access Memory), and is used as a work area for the CPU 101. The auxiliary storage unit 103 is composed of a nonvolatile memory such as a ROM (Read Only Memory), an SSD (Solid State Drive), an HDD (Hard Disk Drive), etc., and stores a program for controlling the base station 1. do. The CPU 101 loads a program stored in the auxiliary storage unit 103 into the main storage unit 102 and executes the program.

The wireless modules 105A, 105B, and 105C each communicate using a communication method compatible with a wireless LAN standard based on, for example, IEEE802.11. The wireless modules 105A, 105B, and 105C each include an antenna (not shown), a receiving circuit (not shown), a signal processing section (not shown), and a transmitting circuit (not shown). The receiving circuit receives a radio signal via an antenna, demodulates a signal corresponding to the received radio signal, generates a baseband signal, and outputs the baseband signal to the signal processing section. The transmitting circuit generates a wireless signal corresponding to a frame to be transmitted by modulating the carrier signal using the baseband signal input from the signal processing unit, and transmits the generated wireless signal via the antenna. The signal processing unit is realized by, for example, a DSP (Digital Signal Processor), and generates a frame corresponding to a wireless signal received by the receiving circuit based on a baseband signal input from the receiving circuit, and sends it to the bus 109. Further, the signal processing section generates a baseband signal based on various frames transferred from the main storage section 102 via the bus 109, and outputs it to the transmission circuit. In this embodiment, the base station 1 includes three wireless modules 105A, 105B, and 105C. For example, the wireless module 105A uses 14 channels belonging to the 2.4 GHz frequency band, and the wireless modules 105B and 105C use 14 channels belonging to the 2.4 GHz frequency band. , channels belonging to W52, W53, and W56, which belong to the 5 GHz frequency band, are used. Note that the wireless modules 105A, 105B, and 105C may be configured with any combination of frequency bands of 2.4 GHz, 5 GHz (W52, W53, W56), and 6 GHz, respectively. For example, the wireless module 105A uses channels in the 2.4 GHz frequency band, the wireless module 105B uses channels in the 5 GHz frequency bands W52 and W53, and the wireless module 105C uses channels in the 6 GHz frequency band. May be available. Furthermore, in this embodiment, the wireless module 105A corresponds to a first wireless module described in the claims, and the wireless modules 105B and 105C correspond to a second wireless module described in the claims. It will be explained as follows. Although each base station 1 according to this embodiment will be described as having three wireless modules 105A, 105B, and 105C, it may have four or more.

In the base station 1, as shown in FIG. It functions as an acquisition section 113, a used channel information acquisition section 114, a used channel determination section 115, a used channel notification section 116, a frame acquisition section 117, and a transmission control section 118. Further, the auxiliary storage unit 103 shown in FIG. 2 is realized by a flash memory, HDD, SSD, etc., and as shown in FIG. and has. Furthermore, the main storage unit 102 shown in FIG. 2 is implemented with a RAM or the like, and as shown in FIG. 3, has a frame buffer 121 that temporarily stores data frames received by the wireless modules 105B and 105C.

For example, as shown in FIG. 4A, the usage status storage unit 131 stores usage status information about each of a plurality of channels belonging to the 5 GHz frequency bands W52, W53, and W56, channel information indicating each of the plurality of channels, and a plurality of channels. are stored in association with a combination of frequency band information indicating the frequency band to which each channel belongs and base station identification information. As will be described later, the usage information stored in the usage status storage unit 131 includes not only information regarding the own station but also usage information transmitted from a lower base station. Here, the usage status information is the number of base stations using these channels for each of a plurality of channels belonging to the frequency bands used by the wireless modules 105B and 105C, for example, 5 GHz frequency bands W52, W53, and W56. It includes information on the number of base stations in use indicating the number of base stations, load factor information indicating the load factor of each of the plurality of channels described above, and noise level information indicating the level of floor noise in each of the plurality of channels described above. The usage information stored in the usage status storage unit 131 includes information regarding the own station and information regarding the lower base station transmitted from the lower base station. As the base station identification information, for example, an SSID (Service Set Identifier) assigned to the wireless module 105A that uses a channel in the 2.4 GHz frequency band can be used. In the example shown in FIG. 4(A), in base station 1B to which base station identification information SSID[1] is assigned, the number of base stations using channel "36ch" belonging to W52 in the 5GHz band is n[1]. , the load factor of channel “36ch” is L[1][%], and the floor noise level of channel “36cn” is P[1][dBm].

For example, as shown in FIG. 4B, the used channel storage unit 132 stores used channel information indicating channels used when transmitting and receiving data frames with other base stations 1 located at higher and lower positions. , is stored in association with base station identification information that identifies the other base station. Here, as the base station identification information, for example, SSID can be adopted. The example shown in FIG. 4(B) is an example of information stored in the used channel storage unit 132 of the base station 1B to which base station identification information SSID[1] is assigned, and which is assigned base station identification information SSID[0]. Transmission and reception of data frames between the base station 1A and the base station 1C assigned the base station identification information SSID[2] uses channel "36ch" belonging to the frequency band W52. This indicates that frame transmission/reception uses channel "52ch" belonging to frequency band W53.

The notification destination storage unit 133 stores information regarding upper and lower base stations that are predetermined notification destinations. The information includes channel information (notification channel information) indicating a channel to be used when transmitting a usage status notification frame to another base station 1, which will be described later, base station identification information that identifies the own station, and preset information. The information includes password information indicating the password entered and MAC address information indicating the MAC (Media Access Control) address of the destination base station 1. Here, when the base station 1A is the highest level, the MAC address indicated by the MAC address information stored in the notification destination storage unit 133 of the base station 1A may be uniquely set. This indicates that there are no more destinations for the usage status notification frame of the base station 1A (that is, it is the highest destination).

The usage status detection unit 111 detects the usage status of each of the three frequency bands W52, W53, and W56, and stores the usage status in the usage status storage unit 131 as shown in FIG. 4(A). Specifically, the usage status detection unit 111 detects, for each of the plurality of channels belonging to the frequency bands W52, W53, and W56, the number of base stations in use, which is the number of base stations 1 using each channel, and the load factor of each channel. and the noise level of the floor noise in each channel. Specifically, the usage status detection unit 111 detects each of a plurality of channels based on the number of types of SSIDs included in frames that arrive at the own station via a plurality of channels belonging to frequency bands W52, W53, and W56, for example. Identify the number of base stations used. In addition, the usage status detection unit 111 detects a plurality of Calculate the load factor for each channel. Further, the usage status detection unit 111 calculates the noise level of floor noise based on the SN ratio when frames are received on each of the plurality of channels belonging to the frequency bands W52, W53, and W56. The usage status detection unit 111 then detects, for the plurality of channels, information on the number of base stations in use indicating the identified number of base stations in use, load factor information indicating the calculated load factor, and noise level information indicating the calculated noise level. , are stored in the usage status storage unit 131 in association with a combination of channel information, frequency band information corresponding to each channel, and base station identification information of the own station.

The usage status notification unit 112 generates a usage status notification that includes usage status information indicating the usage status of each of the plurality of channels detected by the usage status detection unit 111 (that is, information regarding the own station stored in the usage status storage unit 131). A frame is generated, and the generated usage status notification frame is transmitted to a preset base station 1 via a notification channel via the wireless module 105A. Here, the preset base station 1 corresponds to the base station 1 above the own station, and when the base station 1A is above the base station 1B, the usage status notification unit 112 of the base station 1B The usage status notification frame is transmitted to the base station 1A via 105A. Further, when the base station 1B is higher than the base station 1C, the usage status notification unit 112 of the base station 1C transmits a usage status notification frame to the base station 1B via the wireless module 105A. Here, the usage status notification unit 112 generates a usage status notification frame that includes, in addition to the usage status information stored in the usage status storage unit 131, channel information corresponding to the usage status information and base station identification information of the own station. do. Here, as described above, the usage information includes the information on the number of base stations in use, load factor information, and noise level information for each of the plurality of channels. Then, the usage status notification unit 112 transmits the generated usage status notification frame to the notification destination storage unit based on the MAC address information of the preset base station 1 (for example, 1A or 1B) stored in the notification destination storage unit 133. The information is transmitted to another upper base station 1 (for example, 1A or 1B) via a notification channel (for example, a preset channel belonging to the 2.4 GHz frequency band) indicated by the notification channel information stored in 133.

The usage status acquisition unit 113 stores usage status information including usage status information indicating the usage status of each of a plurality of frequency bands in the other base station 1 transmitted from the lower base station 1 stored in the notification destination storage unit 133. A notification frame is acquired via wireless module 105A. Thereafter, the usage status acquisition unit 113 extracts usage status information included in the acquired usage status notification frame, channel information corresponding to each of the usage status information, and source base station identification information. Then, the usage status acquisition unit 113 associates the extracted usage status information, channel information, and base station identification information with each other and stores them in the usage status storage unit 131. Furthermore, the usage status acquisition unit 113 notifies the usage channel notification unit 116 of the base station identification information of the base station 1 (lower base station) that is the transmission source of the usage status notification frame, which is included in the usage status notification frame. This is information to which the specified channel information to be transmitted is sent, as will be described later.

The used channel information acquisition unit 114 is configured to transmit and receive data frames from the upper base station 1 identified by the base station identification information stored in the notification destination storage unit 133 to and from the upper base station 1. A channel-in-use notification frame containing channel-in-use information indicating the channel to be used is obtained via the wireless module 105A. The used channel information acquisition unit 114 extracts the used channel information included in the acquired used channel notification frame, associates the extracted used channel information with the base station identification information of the upper base station 1, and stores it in the used channel storage unit 132. Make me remember. For example, upon acquiring the used channel notification frame transmitted from the upper base station 1A, the used channel information acquisition unit 114 of the base station 1B extracts the used channel information included in the acquired used channel notification frame and stores the used channel information. The information is stored in the section 132. Further, when the used channel information acquisition unit 114 of the base station 1C acquires the used channel notification frame transmitted from the upper base station 1B, the used channel information acquisition unit 114 extracts the used channel information included in the obtained used used channel notification frame and stores the used channel information. The information is stored in the section 132.

The used channel determination unit 115 uses the used channel information notified in advance by the upper base station and stored in the used channel storage unit 132, and the usage status information regarding the own station and lower base stations stored in the usage status storage unit 131. Based on this, the channel to be used for transmitting and receiving the data frame with the other base station 1 (lower base station) that is the transmission source of the usage status notification frame is determined. Here, the usage channel determination unit 115 determines whether the usage channel belonging to one of the three frequency bands W52, W53, and W56 in the 5 GHz band is different from the frequency band to which the usage channel set from the upper base station belongs. The channel is determined to be the above-mentioned channel to be used. Specifically, the usage channel determination unit 115 sets a channel to be used that is different from the usage channel set from the upper base station, but more preferably, it uses a frequency to which the usage channel set from the higher base station belongs. From the channels belonging to a frequency band different from the frequency band, first, by referring to the information on the number of base stations in use for each of the plurality of channels stored in the usage status storage unit 131, select the channel with the smallest number of base stations in use among the plurality of channels. Identify. Here, if there is only one channel with the minimum number of base stations in use, the channel-in-use determining unit 115 determines that one channel as the channel in use. On the other hand, if there are multiple channels with the minimum number of base stations in use, the usage channel determination unit 115 refers to the load factor information of each of the channels with the minimum number of base stations in use, which is stored in the usage status storage unit 131. , the channel with the minimum load factor is identified from among the channels with the minimum number of base stations in use. Here, if there is only one channel with the minimum load factor, the used channel determination unit 115 determines that one channel as the used channel. On the other hand, if there are multiple channels with the minimum load factor, the usage channel determination unit 115 further refers to the noise level information of each of the channels with the minimum load factor stored in the usage status storage unit 131, and determines the load factor. Identify the channel with the minimum noise level from among the channels with the minimum noise level. Here, if there is only one channel with the lowest noise level, the usage channel determining unit 115 determines that one channel as the usage channel. On the other hand, if there are a plurality of channels with the minimum noise level, the usage channel determination unit 115 identifies one channel from among the channels with the minimum noise level, and determines the identified channel as the usage channel. Here, the used channel determination unit 115 may specify, for example, the channel whose channel number indicated by the channel information is the lowest. Further, the channel-in-use determination unit 115 stores the channel-in-use information indicating the channel in use thus determined in the channel-in-use storage unit 132 in association with the base station identification information of the corresponding lower base station 1.

In addition, in the above description, the usage channel determining unit 115 selects one of the three frequency bands W52, W53, and W56 in the 5 GHz band, which is different from the frequency band to which the usage channel corresponding to the preset base station 1 belongs. Although channels belonging to a frequency band are specified, it may be another channel belonging to the same frequency band of frequency bands W52, W53, and W56 (for example, specifying channel 60 for channel 52 of W53 whose bands are not adjacent to each other). etc.).

The used channel notification unit 116 sends the used channel notification frame including used channel information indicating the used channel determined by the used channel determination unit 115 to another base station 1 (which is the transmission source of the usage status notification frame) via the wireless module 105A. lower base station). For example, when the usage channel notification unit 116 of the base station 1A receives the usage status notification frame from the base station 1B, it transmits the determined usage channel notification frame to the base station 1B. Further, when the usage channel notification unit 116 of the base station 1B receives the usage status notification frame from the base station 1C, it transmits the determined usage channel notification frame to the base station 1C.

Frame acquisition unit 117 determines whether a connection request frame or a connection permission frame has been received in wireless modules 105A, 105B, and 105C, and transmits the determination result to usage status detection unit 111, usage status acquisition unit 113, or The transmission control unit 118 is notified. Further, the data frames received by the wireless modules 105B and 105C are acquired, and the acquired data frames are stored in the frame buffer 121.

The transmission control unit 118 controls the transmission of the data frame stored in the frame buffer 121 to other base stations 1 based on the usage channel information stored in the usage channel storage unit 132.

Next, the operation of the communication system according to this embodiment will be described in detail with reference to FIGS. 5 and 6. Here, a case will be described in which the base station 1A is the highest level, the base station 1A is above the base station 1B, and the base station 1B is above the base station 1C. Further, here, a case will be described in which data frames are transmitted and received via the wireless modules 105B and 105C.

First, as shown in FIG. 5, the base station 1A detects the usage status of each of a plurality of channels that belong to the frequency band used by the wireless module 105B (step S1), and also detects the usage status of each of a plurality of channels that belong to the frequency band used by the wireless module 105C. The usage status of each of the plurality of channels is detected (step S2). Then, the base station 1A stores usage status information indicating the detected usage status in the usage status storage unit 131 of the base station 1A. Similarly, the base station 1B also detects the usage status of each of the plurality of channels belonging to the frequency band used by the wireless module 105B (step S3), and also detects the usage status of each of the plurality of channels belonging to the frequency band used by the wireless module 105C. The situation is detected (step S4). Then, the base station 1B stores usage status information indicating the detected usage status in the usage status storage unit 131 of the base station 1B. Furthermore, the base station 1C also detects the usage status of each of the multiple channels belonging to the frequency band used by the wireless module 105B (step S5), and also detects the usage status of each of the multiple channels belonging to the frequency band used by the wireless module 105C. is detected (step S6). Then, the base station 1C stores usage status information indicating the detected usage status in the usage status storage unit 131 of the base station 1C.

Next, the base station 1B transmits an authentication request frame to the base station 1A via the wireless module 105A, and then receives an authentication response frame transmitted from the base station 1A at the wireless module 105A (not shown). Assume that authentication such as open system authentication is successful. In this case, a connection request frame containing SSID information indicating the SSID assigned to the wireless module 105A of the base station 1B is transmitted from the wireless module 105A of the base station 1B to the wireless module 105A of the base station 1A via the notification channel ( Step S7). On the other hand, when the base station 1A acquires a connection request frame via the wireless module 105A, a connection permission frame corresponding to the connection request frame is sent for notification from the wireless module 105A of the base station 1A to the wireless module 105A of the base station 1B. channel (step S8).

On the other hand, upon receiving the connection permission frame via the wireless module 105A, the base station 1B generates a usage status notification frame including usage status information stored in the usage status storage unit 131 (step S9). Subsequently, the generated usage status notification frame is transmitted from the wireless module 105A of the base station 1B to the wireless module 105A of the base station 1A via the notification channel (step S10). On the other hand, when the base station 1A receives the usage status notification frame via the wireless module 105A, the base station 1A stores the usage status information included in the received usage status notification frame in the usage status storage unit 131. The base station 1A uses the usage status information of the base station 1A and the usage status information of the base station 1B stored in the usage status storage unit 131 when transmitting and receiving data frames to and from the base station 1B. A channel to be used is determined (step S11). After that, the base station 1A generates a used channel notification frame including used channel information indicating the determined used channel (step S12), and the generated used channel notification frame is transferred from the wireless module 105A of the base station 1A to the base station 1B. is transmitted to the wireless module 105A via the notification channel (step S13).

On the other hand, upon receiving the used channel notification frame via the wireless module 105A, the base station 1B stores the used channel information included in the received used channel notification frame in the used channel storage unit 132. This used channel information indicates a channel belonging to the frequency band used by the wireless module 105B, and hereinafter data communication between the base station 1A and the base station 1B is performed using a channel stored in this used channel storage unit (first used channel (equivalent to). It is assumed that authentication is successful when the base station 1B transmits an authentication request frame to the base station 1A via the wireless module 105B and then receives an authentication response frame transmitted from the base station 1A at the wireless module 105B (not shown). ). In this case, a connection request frame including SSID information indicating the SSID assigned to the wireless module 105B of the base station 1B is sent from the base station to the wireless module 105B of the base station 1B using the usage channel stored in the usage channel storage unit 132. It is transmitted to the wireless module 105B of 1A (step S14). On the other hand, when the base station 1A receives a connection request frame via the wireless module 105B, a connection permission frame corresponding to the connection request frame is transmitted from the wireless module 105B of the base station 1A to the wireless module 105B of the base station 1B. (Step S15).

After that, it is assumed that the base station 1C transmits an authentication request frame to the base station 1B via the wireless module 105A, and then the wireless module 105A receives an authentication response frame transmitted from the base station 1B, so that authentication is successful. In this case, a connection request frame containing SSID information indicating the SSID assigned to the wireless module 105A of the base station 1C is transmitted from the wireless module 105A of the base station 1C to the wireless module 105A of the base station 1B (step S16). On the other hand, when the base station 1B receives a connection request frame via the wireless module 105A, a connection permission frame corresponding to the connection request frame is transmitted from the wireless module 105A of the base station 1B to the wireless module 105A of the base station 1C. (Step S17).

When the base station 1C receives the connection permission frame via the wireless module 105A, it generates a usage status notification frame including usage status information stored in the usage status storage unit 131 (step S18). Next, the generated usage status notification frame is transmitted from the wireless module 105A of the base station 1C to the wireless module 105A of the base station 1B via the notification channel (step S19). On the other hand, as shown in FIG. 6 below, when the base station 1B receives the usage status notification frame via the wireless module 105A, the base station 1B stores the usage status information included in the received usage status notification frame in the usage status storage unit 131. . The base station 1B uses the usage status information of the base station 1B and the usage status information of the base station 1C stored in the usage status storage unit 131 for data frame communication with the base station 1A stored in the usage channel storage unit 132. Based on the usage channel information, the usage channel (corresponding to the second usage channel) to be used when transmitting/receiving the data frame with the base station 1C is determined (step S20). As this used channel, a channel different from the used channel used for data communication with the base station 1A is selected. Preferably, the used channel is a channel in a frequency band different from the used channel used for data communication with the base station 1A. Subsequently, the base station 1B generates a used channel notification frame including used channel information indicating the determined used channel (step S21), and the generated used channel notification frame is transmitted to the wireless module of the base station 1B via the notification channel. 105A to the wireless module 105A of the base station 1C (step S22).

On the other hand, upon receiving the used channel notification frame via the wireless module 105A, the base station 1C stores the used channel information included in the received used channel notification frame in the used channel storage unit 132. This used channel information indicates a channel belonging to the frequency band used by the wireless module 105C, and data communication between the base station 1B and the base station 1C is performed using the channel stored in this used channel storage section. It is assumed that authentication is successful when the base station 1B transmits an authentication request frame to the base station 1B via the wireless module 105C and then receives an authentication response frame transmitted from the base station 1B at the wireless module 105C (not shown). ). In this case, a connection request frame containing SSID information indicating the SSID assigned to the wireless module 105C of the base station 1C is transmitted from the wireless module 105C of the base station 1C to the wireless module 105C of the base station 1B (step S23). On the other hand, when the base station 1B receives a connection request frame via the wireless module 105C, a connection permission frame corresponding to the connection request frame is transmitted from the wireless module 105C of the base station 1B to the wireless module 105C of the base station 1C. (Step S24).

After that, when the base station 1A receives a data frame addressed to the terminal device 3E or 3F under the base station 1C from the terminal device 3A or 3B under its own station (step S25), the acquired data frame is is transmitted from the wireless module 105B of the base station 1B to the wireless module 105B of the base station 1B (step S26). On the other hand, when the base station 1B receives the data frame via the wireless module 105B, the received data frame is transmitted from the wireless module 105C of the base station 1B to the wireless module 105C of the base station 1C (step S27). Note that the channel used for transmission from base station 1A to base station 1B is different from the channel used for transmission from base station 1B to base station 1C. This avoids reception and transmission channel interference in the base station 1B, and suppresses a decrease in throughput in data frame transmission. On the other hand, upon receiving the data frame via the wireless module 105C, the base station 1C transmits the received data frame to the terminal devices 3E and 3F (step S28).

Next, communication control processing executed by the base station 1 according to the present embodiment will be described in detail with reference to FIGS. 7 to 9. This communication control process is started, for example, when the base station 1 is powered on. Here, the communication control processing of the base station 1 will be explained separately for the upper base station 1 (FIGS. 7 and 8) and the lower base station 1 (FIG. 9). Here, detailed explanation will be given on the premise that, for example, the base station 1A is the upper base station 1 and the base station 1B is the lower base station 1.

First, communication control processing of the upper base station 1 (base station 1A) will be explained using FIG. 7. As shown in FIG. 7, the usage status detection unit 111 of the base station 1A detects the usage status of each of the plurality of frequency bands W52, W53, and W56 in the 5 GHz band (step S101). Next, the usage status acquisition unit 113 receives the authentication request frame from the lower base station 1 (base station 1B) via the wireless module 105A, and receives the corresponding authentication response frame via the wireless module 105A. It is assumed that the received authentication request frame is sent to the source and the authentication is successful. The frame acquisition unit 117 determines whether a connection request frame including SSID information of the wireless module 105A of the lower base station 1 has been received (step S102). If it is determined that a connection request frame has been received, the usage status acquisition unit 113 is notified of this, and the process moves to step S103 (step S102: Yes). On the other hand, if it is determined that the connection request frame has not been received, the process of step S102 is repeated (step S102: No). Next, the usage status acquisition unit 113 transmits the connection permission frame to the lower base station 1 (base station 1B) that is the source of the connection request frame via the wireless module 105A (step S103). Subsequently, the usage status acquisition unit 113 determines whether a usage status notification frame has been received (step S104). If it is determined that the usage status notification frame has been received, the process moves to step 105 (step S104: Yes). On the other hand, if it is determined that the usage status notification frame has not been received, the process of step S104 is repeated (step S104: No). The used channel determination unit 115 determines the lower base station 1 (base station A channel to be used for transmitting and receiving data frames to and from station 1B is determined (step S105).

Here, the usage channel determination process (step S105 in FIG. 7) executed by the usage channel determination unit 115 will be described in detail with reference to FIG. 8. The used channel determination unit 115 first refers to the load factor information of each of the plurality of channels stored in the usage status storage unit 131, and identifies the channel with the minimum load factor from among the plurality of channels (step S201). Next, the used channel determination unit 115 determines whether there are a plurality of channels with the minimum load factor (step S202). Here, if the channel-in-use determination unit 115 determines that there is only one channel with the minimum load factor (step S202: No), it determines the identified one channel as the channel in use (step 208). On the other hand, if the usage channel determination unit 115 determines that there are multiple channels with the minimum load factor (step S202: Yes), the usage status storage unit 131 stores the number of usage base stations for each of the multiple channels with the minimum load ratio. With reference to the information, a channel with the minimum number of base stations in use is specified from among the channels with the minimum load factor (step S203).

Subsequently, the used channel determination unit 115 determines whether there are a plurality of channels with the minimum number of used base stations (step S204). Here, if the channel-in-use determining unit 115 determines that there is only one channel with the minimum number of base stations in use (step S204: No), it determines the identified one channel as the channel in use (step S208). On the other hand, if the usage channel determination unit 115 determines that there are multiple channels with the minimum number of base stations in use (step S204: Yes), the usage status storage unit 131 stores the noise level of each of the multiple channels with the minimum load factor. With reference to the information, a channel with the minimum noise level is specified from among the channels with the minimum load factor (step S205).

Thereafter, the used channel determining unit 115 determines whether there are a plurality of channels with the lowest noise level (step S206). Here, if the usage channel determining unit 115 determines that there is only one channel with the minimum noise level (step S206: No), it determines the identified one channel as the usage channel (step S208). On the other hand, when the channel-in-use determining unit 115 determines that there are multiple channels with the lowest noise level (step S206: Yes), it identifies one channel from among the channels with the lowest noise level (step S207). One channel is determined to be the channel to be used (step S208). Here, the usage channel determining unit 115 stores the usage channel information indicating the determined usage channel in the usage channel storage unit 132 in association with the base station identification information of the corresponding base station 1.
Although not shown in FIG. 8, if there is an upper base station for such a base station, in the usage channel determination process, the channel included in the usage channel information transmitted from the upper base station is excluded from candidates. will be done.

Returning to FIG. 7, next, the used channel notification unit 116 generates a used channel notification frame including used channel information indicating the used channel determined by the used channel determination unit 115, and transmits the generated used channel notification frame to the lower to base station 1 (base station 1B) (step S106). Next, the frame acquisition unit 117 determines whether or not a connection request frame including SSID information indicating the SSID assigned to the wireless module 105B of the lower base station 1 (base station 1B) has been received (step S107). . If it is determined that a connection request frame has been received, the usage status acquisition unit 113 is notified of this, and the process moves to step 108 (step S107: Yes). On the other hand, if it is determined that the connection request frame has not been received, the process of step S107 is repeated (step S107: No). Here, the usage status acquisition unit 113 receives the authentication request frame from the lower base station 1 (base station 1B) via the wireless module 105B, and receives the corresponding authentication response frame via the wireless module 105B. It is assumed that the received authentication request frame is transmitted to the lower base station 1 (base station 1B) from which it was sent, and that authentication is successful. The usage status acquisition unit 113 transmits a connection permission frame corresponding to the connection request frame to the wireless module 105B of the lower base station 1 (base station 1B) via the wireless module 105B of the base station 1A (step S108). Thereafter, data can be transmitted and received between the wireless module 105B of the base station 1A and the wireless module 105B of the base station 1B (step 109).

Next, communication control processing of the lower base station 1 (base station 1B) will be explained. As shown in FIG. 9, the usage status detection unit 111 of the base station 1B detects the usage status of each of a plurality of frequency bands W52, W53, and W56 in the 5 GHz band (step S301). Here, the usage status acquisition unit 113 transmits an authentication request frame to the upper base station 1 (base station 1A) via the wireless module 105A, and sends a corresponding authentication response frame from the receiving source of the authentication request frame. It is assumed that the reception and authentication are successful via the wireless module 105A. The usage status notification unit 112 of the base station 1B sends a connection request frame containing the SSID information of the wireless module 105A of the upper base station 1 (base station 1A) to the upper base station 1 (base station 1A) via the wireless module 105A. ) (step S302). Subsequently, the frame acquisition unit 117 of the base station 1B determines whether a connection permission frame transmitted from the upper base station 1 (base station 1A) via the wireless module 105A has been received (step S303). If it is determined that a connection request frame has been received, the usage status detection unit 111 is notified of this, and the process moves to step S304 (step S303: Yes). On the other hand, if it is determined that the connection permission frame has not been received, the process of step S303 is repeated (step S303: No). Next, the usage status notification unit 112 generates a usage status notification frame including usage status information indicating the usage status of each of the plurality of channels detected by the usage status detection unit 111, and transmits the generated usage status notification frame to the wireless It is transmitted to the upper base station 1 (base station 1A) via the module 105A (step S304). Subsequently, the used channel information acquisition unit 114 determines whether a used channel notification frame has been received from the upper base station 1 (base station 1A) (step S305). If it is determined that the used channel notification frame has been received, the used channel information included in the received used channel notification frame is stored in the used channel storage unit 132, and the process moves to step 306 (step S305: Yes). On the other hand, if it is determined that the used channel notification frame has not been received, the process of step S305 is repeated (step S305: No). Next, a connection request frame including SSID information indicating the SSID assigned to the wireless module 105B of the base station 1B is transmitted from the wireless module 105B of the base station 1B to the base station 1A using the usage channel stored in the usage channel storage unit 132. wireless module 105B (step S306). Subsequently, the frame acquisition unit 117 determines whether or not a connection permission frame, which is a response to the connection request frame, has been received from the wireless module 105B of the upper base station 1 (base station 1A) (step S307). If it is determined that a connection permission frame has been received, the transmission control unit 118 is notified of this, and the process moves to step 308 (step S307: Yes). On the other hand, if it is determined that the connection permission frame has not been received, the process of step S307 is repeated (step S307: No). Thereafter, data can be transmitted and received between the wireless module 105B of the base station 1A and the wireless module 105B of the base station 1B (step 308).

As explained above, according to the base station 1 according to the present embodiment, the usage channel determination unit 115 determines the usage channel used for transmitting and receiving data frames with other lower base stations 1. The usage status showing the usage status of each of the three frequency bands W52, W53, and W56 of the own station, while avoiding the usage channels notified as being used for transmitting and receiving data frames with other base stations 1. The determination is made based on the information and second usage status information indicating the usage status of each of the three frequency bands W52, W53, and W56 in other lower base stations 1. As a result, the channel used for transmitting and receiving data frames with the upper base station 1 and the channel used for transmitting and receiving data frames with the lower base station 1 are different, and the channel used for transmitting and receiving data frames with the lower base station 1 is different. When transmitting/receiving data frames from a subordinate slave device to a subordinate slave device of an upper base station 1 and a lower base station 1, it becomes easier to secure a band required for wireless communication between the respective base stations. Therefore, it is possible to suppress a decrease in throughput in data frame transmission due to a shortage of bandwidth that occurs in conventional WDS communication in which wireless communication between base stations is performed using one channel.

(Embodiment 2)
The base station according to the present embodiment determines whether radar waves are detected in any of the channels belonging to the second frequency band to which the channel used for transmitting and receiving data frames with other base stations belongs. This embodiment differs from Embodiment 1 in that it includes a detection and determination section that determines whether In the base station according to the present embodiment, when the detection and determination unit determines that a radar wave is detected in the above-mentioned used channel, the transmission control unit temporarily assigns the used channel to the first frequency band. changing the channel and transmitting the data frame to another base station via the first wireless module. The first frequency band means a band that does not overlap with the frequency band used by radar waves, and is, for example, the W52 band of the 2.4 GHz band or 5 GHz band. On the other hand, the second frequency band is a frequency band of 5 GHz and 6 GHz suitable for transmitting data frames, but more specifically, for example, it is a band of the 5 GHz band that includes the W53 and W56 bands used by radar waves. .

The hardware configuration of the base station according to the present embodiment is similar to the hardware configuration of the base station 1 described in the first embodiment. Hereinafter, configurations similar to those in Embodiment 1 will be described using the same reference numerals as in FIGS. 1 and 2 as appropriate. In the base station 2001 according to the present embodiment, the CPU 101 shown in FIG. 111, functions as a usage status notification unit 112, usage status acquisition unit 113, usage channel information acquisition unit 114, usage channel determination unit 115, usage channel notification unit 2116, frame acquisition unit 117, transmission control unit 2118, and detection determination unit 2119. . Note that in FIG. 10, the same components as in Embodiment 1 are given the same reference numerals as in FIG. 3. Further, the auxiliary storage unit 103 shown in FIG. 2 includes a usage status storage unit 131, a usage channel storage unit 2132, and a notification destination storage unit 133, as shown in FIG. Furthermore, the main storage unit 102 shown in FIG. 2 includes a frame buffer 121 that temporarily stores frames received by the wireless modules 105A and 105B, as shown in FIG. 10. As shown in FIG. 11, the used channel storage unit 2132 stores used channel information indicating a channel normally used when transmitting a data frame to each other base station and a channel used when a radar wave is detected. , and are stored in association with base station identification information that identifies other base stations. In the example shown in FIG. 11, the channels normally used for transmitting and receiving data frames are set to channels belonging to the 5 GHz frequency bands W53 and W56, and the channels used when radar waves are detected (first frequency (equivalent to channels in the band) are set to channels (1ch and 11ch) belonging to the 2.4 GHz frequency band.

Returning to FIG. 10, the detection determination unit 2119 detects that the frequency of the channel used for transmitting and receiving data frames with other base stations 1 (upper and lower base stations) is determined in a preset monitoring cycle. It is determined whether a radar wave is detected in one of the channels belonging to the band W53 or W56. When the detection determination unit 2119 determines that the above-mentioned channel in use is a channel belonging to the frequency band W53 or W56 and radar waves have been detected in one of them, the detection determination unit 2119 uses the information indicating that radar waves have been detected in the channel in use. The channel notification section 2116 and transmission control section 2118 are notified.

The transmission control unit 2118 determines that the channel in use has detected a radar wave by the detection determination unit 2119, and when the radar wave in the second frequency band is detected, the transmission control unit 2118 selects a frequency band (for example, a 5 GHz band) that needs to be changed to a different channel when a radar wave is detected in the second frequency band. W53 and W56), stop communication on the used channel determined to have detected the radar wave, change to a channel belonging to the first frequency band, for example, 2.4 GHz frequency band, and change the data frame to It is transmitted to another base station 1 via the wireless module 105A. Specifically, when the transmission control unit 2118 is notified by the detection determination unit 2119 that it has been determined that radar waves have been detected, the transmission control unit 2118 selects the channel to be used, which is stored in the usage channel storage unit 2132, when the radar wave has been detected. The data frame is changed to the 2.4 GHz band channel as in the case where the data frame is transmitted to another base station 1 via the wireless module 105A. Furthermore, the transmission control unit 2118 may change the used channel to a channel in which radar waves are not detected (channels belonging to the 5 GHz frequency bands W53 and W56) among the second frequency bands. When a preset carrier sense time has elapsed, the transmission control unit 2118 may change the changed usage channel to the channel determined by the usage channel determination unit 115 again. Here, the carrier sense time is set to, for example, 30 minutes.

When the used channel notification unit 2116 is notified by the detection determination unit 2119 that a radar wave has been detected on the used channel, the used channel notification unit 2116 detects the radar wave corresponding to the notified frequency band information stored in the used channel storage unit 2132. Specify the channel to be used (for example, a channel in the 2.4 GHz band) when Then, the used channel notification unit 2116 generates a temporarily used channel notification frame including used channel information indicating the specified used channel, and sends the generated temporarily used channel notification frame to the wireless module 105A when a radar wave is detected. Channels belonging to frequency bands W53 and W56 are transmitted to other base stations 1 in use. In addition, when the aforementioned carrier sense time has elapsed after the transmission control unit 2118 changed the channel to be used, the channel-to-be-used notification unit 2116 transmits a channel to the channel that includes the channel-to-be-used information indicating the channel to be used determined by the channel-to-be-used determining unit 115. A recovery notification frame is generated, and the generated channel recovery notification frame is transmitted via the wireless module 105A to another base station 1 that uses the changed channel.

Next, the operation of the communication system according to this embodiment will be described in detail with reference to FIG. 12. Note that in FIG. 12, the same processes as in Embodiment 1 are given the same reference numerals as in FIGS. 5 and 6. 5 and 6, here, the upper base station of base station 2001B is base station 2001A, the upper base station of base station 2001C is base station 2001B, and wireless modules 105B and 105C are used. A case in which a data frame is transmitted and received will be explained. First, assume that after the series of processes up to step S28 described in Embodiment 1 has been executed, the base station 2001B detects radar waves in the frequency band to which the channel used by the wireless module 105B belongs (step S2001). . Specifically, suppose that it is determined that the base station 2001B has detected a radar wave on the channel used by the wireless module 105B. In this case, the base station 2001B identifies the channel to be used when the radar wave is detected, which is stored in the channel-to-be-used storage unit 2132, and generates a temporary channel notification frame containing channel information indicating the identified channel to be used ( Step S2002). Next, the generated temporary channel notification frame is transmitted from the wireless module 105A of the base station 2001B to the wireless module 105A of the base station 2001A (step S2003). Subsequently, the base station 2001B changes the channel used for transmitting and receiving data frames with the base station 2001A to the channel used when radar waves are detected (step S2004).

On the other hand, upon receiving the temporary use channel notification frame, the base station 2001A changes the use channel to the channel indicated by the use channel information included in the received temporary use notification frame (step S2005). Thereafter, the data frame is transmitted from the wireless module 105A of the base station 2001A to the wireless module 105A of the base station 2001B via the changed usage channel (step S2006).

Next, assume that the base station 2001B determines that the carrier sense time described above has elapsed after changing the channel used (step S2007). In this case, the base station 2001B generates a channel-in-use return notification frame that includes channel-in-use information indicating the channel in use determined by the channel-in-use determination unit 115 (step S2008). Subsequently, the generated channel return notification frame is transmitted from the wireless module 105A of the base station 2001B to the wireless module 105A of the base station 2001A (step S2009). After that, the base station 2001B changes the channel to be used for transmitting and receiving data frames to and from the base station 2001A to the channel to be used again determined by the channel to be used determining unit 115 (step S2010).

On the other hand, upon receiving the used channel return notification frame, the base station 2001A changes the used channel to the channel indicated by the used channel information included in the received used channel return notification frame (step S2011). Next, the data frame is again transmitted from the wireless module 105A of the base station 2001A to the wireless module 105A of the base station 2001B via the usage channel determined by the usage channel determination unit 115 (step S2012).

Next, communication control processing executed by base station 1 according to the present embodiment will be described in detail with reference to FIG. 13. Here, it is assumed that transmission and reception of data frames has already started. Furthermore, the base station 1 communicates wirelessly with a plurality of other base stations 1 on a different channel. First, the used channel notification unit 2116 determines whether a radar wave is detected in any of the used channels used for transmitting and receiving data frames with other base stations 1 by the detection determining unit 2119 (step S2101). Here, as long as the used channel notification unit 2116 determines that radar waves are not detected for all of the used channels used for transmitting and receiving data frames (step S2101: No), the process of step S2101 is repeated again.

On the other hand, assume that the used channel notification unit 2116 determines that a radar wave is detected on the used channel used for transmitting and receiving data frames with other base stations 1 (step S2101: Yes). In this case, when the used channel notification unit 2116 is notified by the detection determination unit 2119 that radar waves have been detected on the used channel, the used channel notification unit 2116 selects the used channel when the radar wave is detected, which is stored in the used channel storage unit 2132. Identify. Then, the used channel notification unit 2116 generates a temporarily used channel notification frame including used channel information indicating the specified used channel, and transmits the generated temporary used channel notification frame via the wireless module 105A using the channel. It is transmitted to the base station 1 of the communication partner (step S2102).

Subsequently, when the transmission control unit 2118 is notified by the detection determination unit 2119 that radar waves have been detected on the used channel, the transmission control unit 2118 changes the used channel to the used channel stored in the used channel storage unit 2132 when radar waves are detected. The channel is changed to the used channel (step S2103).

Thereafter, the channel-in-use notification unit 2116 determines whether the carrier sense time described above has elapsed after the transmission control unit 2118 changed the channel in use (step S2104). Here, if the used channel notification unit 2116 determines that the carrier sense time has not yet elapsed (step S2104: No), it repeats the process of step S2104 again. On the other hand, it is assumed that the used channel notification unit 2116 determines that the carrier sense time has elapsed (step S2104: Yes). In this case, the used channel notification unit 2116 generates a used channel return notification frame that includes used channel information indicating the used channel determined by the used channel determination unit 115, and transmits the used used channel return notification frame to the wireless module 105A. via the changed channel to another base station 1 that uses the changed channel (step S2105). Next, the transmission control unit 2118 changes the changed channel to be used again to the channel determined by the channel to be used determining unit 115 (step S2106). Subsequently, the process of step S2101 is executed again.

As explained above, according to the base station 2001 according to the present embodiment, the detection determination unit 2119 determines whether one of the channels used for transmitting and receiving data frames with another base station 2001 is detected. Determine whether radar waves are detected. Then, the transmission control unit 2118 changes the channel used in which the radar wave was detected to the channel used when the detection determination unit 2119 determines that the radar wave was detected, and transmits the data frame to the first wireless module. to other base stations via the base station. Thereby, when radar waves are detected on the channel to be used determined by the channel to be used determining section 115, it is possible to continue transmitting data frames to other base stations 1 even within the carrier sense time. Therefore, reduction in throughput in data frame transmission due to interference with radar waves can be suppressed.

(Modified example)
Although each embodiment of the present invention has been described above, the present invention is not limited to the configuration of each of the above-described embodiments. For example, base station 1 (for example, 1B, 1C) may transmit usage status notification information to upper base station 1 (for example, 1A, 1B) using TCP/IP. In this case, the notification destination storage unit 133 may store IP address information indicating the IP address of the base station 1 to which the usage status notification frame is transmitted. Then, the usage status notification unit 112 may generate a usage status notification frame including TCP header information and IP header information and transmit it to the upper base station 1.

In each embodiment, the frequency band used by the wireless module 105A is not limited to the 2.4 GHz frequency band; for example, the wireless module 105A uses the frequency band W52, and the wireless modules 105B and 105C use the frequency band W52. Either channel belonging to bands W53 and W56 may be used. In this case, even when radar waves are detected, there is no need to change the wireless module for transmitting and receiving data frames to 105A for 2.4 GHz.

In each embodiment, the base station 1, 2001 is capable of communicating with other base stations 1, 2001 not only in the 2.4 GHz frequency band, the 5 GHz frequency bands W52, W53, and W56, but also in the 6 GHz frequency band. There may be. Here, the 6 GHz frequency band has a bandwidth of 20 MHz and 60 channels. In this case, the base station 1, 2001 may include five wireless modules corresponding to each of the five frequency bands, or both the 2.4 GHz frequency band and the 5 GHz frequency band may be implemented as one wireless module. Alternatively, both the 5 GHz frequency band and the 6 GHz frequency band may be realized by one wireless module, and the combination of wireless modules corresponding to each of the five frequency bands is free. In this case, for example, as shown in FIG. 14, eight base stations 1A, 1B, 1C, 1D, 1E, 1F, 1G, and 1H each have four frequency bands (5 GHz frequency band) suitable for transmitting and receiving data frames. W53, W54, W56, and 6 GHz bands), and use channels belonging to different frequency bands for adjacent wireless communication links. It can be configured as follows. In this case, it is preferable that the usage status notification frame and the usage channel notification frame be transmitted and received using a channel in the 2.4 GHz frequency band, where communication is less likely to be interrupted.

In each embodiment, the base station 1, 2001 may include only one wireless module 105, and one wireless module 105 may function as three virtual wireless modules 105A, 105B, and 105C.

In each embodiment, the used channel determination unit 115 determines the used channel based on the number of used base stations, the load factor, and the noise level for each of the channels belonging to three frequency bands W52, W53, and W56. An example was explained. However, the present invention is not limited to this, and the used channel determining unit 115 may select only one or two types of the number of base stations used, the load factor, and the noise level for each of the channels belonging to the three frequency bands W52, W53, and W56. Based on this, the channel to be used may be determined. Further, in each embodiment, an example has been described in which the channel-to-be-used determining unit 115 determines the channel to be used by determining the load factor, the number of base stations in use, and the noise level in this order, but this order is not particularly limited. .

Various functions of the base stations 1 and 2001 according to the present invention can be realized using a computer system including a wireless communication module, without using a dedicated system. For example, a program for executing the above operations is stored and distributed to a computer connected to a network in a non-temporary recording medium (such as a CD-ROM) that can be read by the computer system, and the program is transferred to a computer connected to a network. By installing it in the system, the base station 1, 2001 that executes the above-described processing may be configured.

Further, the method of providing the program to the computer is arbitrary. For example, the program may be uploaded to a server on a communication line and distributed to a computer via the communication line. Then, the computer starts this program and executes it like any other application under the control of the OS. Thereby, the computer functions as a base station 1, 2001 that executes the above-described processing.

Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to these. The present invention includes combinations of the embodiments and modifications as appropriate, and modifications as appropriate.

INDUSTRIAL APPLICATION This invention is suitable as a base station which constructs a wireless LAN network by a WDS function.

1, 1A, 1B, 1C, 2001, 2001A, 2001B, 2001C: Base station, 3, 3A, 3B, 3C, 3D, 3E, 3F: Terminal device, 101: CPU, 102: Main storage unit, 103: Auxiliary storage 105A, 105B, 105C: Wireless module, 109: Bus, 111: Usage status detection unit, 112: Usage status notification unit, 113: Usage status acquisition unit, 114: Usage channel information acquisition unit, 115: Usage channel determination unit , 116, 2116: Usage channel notification unit, 117: Frame acquisition unit, 118, 2118: Transmission control unit, 121: Frame buffer, 131: Usage status storage unit, 132, 2132: Usage channel storage unit, 133: Notification destination storage Section, 2119: Detection discrimination section

Claims (12)

a plurality of wireless modules that wirelessly communicate with a plurality of other base stations through channels belonging to one of a plurality of frequency bands;
First used channel information indicating a first used channel used for transmitting and receiving data frames to and from the first base station, which is transmitted from a preset first base station among the other plurality of base stations. a usage channel information acquisition unit that acquires the
A channel different from the first used channel is used as a second used channel used for transmitting and receiving data frames with a second base station different from the first base station among the other plurality of base stations. a usage channel determination unit that determines;
a used channel notification unit that transmits second used channel information indicating the determined second used channel to the second base station via one of the plurality of wireless modules;
base station. a plurality of wireless modules that wirelessly communicate with a plurality of other base stations through channels belonging to one of a plurality of frequency bands;
First used channel information indicating a first used channel used for transmitting and receiving data frames to and from the first base station, which is transmitted from a preset first base station among the other plurality of base stations. a usage channel information acquisition unit that acquires the
A channel belonging to any one frequency band different from the first used channel among the plurality of frequency bands is used as a second base station different from the first base station among the other plurality of base stations. a usage channel determination unit that determines a second usage channel to be used for transmitting and receiving data frames between the
a used channel notification unit that transmits second used channel information indicating the determined second used channel to the second base station via one of the plurality of wireless modules;
base station. a usage status detection unit that detects usage status of each of the plurality of frequency bands;
a usage status notification unit that transmits first usage status information indicating the detected usage status to the first base station via one of the plurality of wireless modules;
A usage status in which second usage status information indicating a usage status of each of the plurality of frequency bands in the second base station transmitted from the second base station is acquired via any one of the plurality of wireless modules. further comprising an acquisition unit;
The base station according to claim 1 or 2, wherein the usage channel determination unit determines the second usage channel based on the first usage channel information, the first usage status information, and the second usage status information. . The plurality of frequency bands include a first frequency band and at least one second frequency band different from the first frequency band,
The plurality of wireless modules include:
a first wireless module that communicates with the other plurality of base stations through a channel belonging to the first frequency band;
a plurality of second wireless modules that wirelessly communicate with other base stations through channels belonging to the second frequency band;
the first usage channel and the second usage channel belong to the at least one second frequency band;
the first usage status information, the first usage channel information, the second usage status information, and the second usage channel information are transmitted and received by the first wireless module;
The base station according to claim 3. The plurality of frequency bands include a plurality of second frequency bands,
The channel-in-use determining unit determines, based on the first usage status information and the second usage status information, a second frequency band that is different from a second frequency band to which the first usage channel belongs among the plurality of second frequency bands. determining one of the channels belonging to the second frequency band as the second used channel;
The base station according to claim 3 or 4. The first usage status information and the second usage status information include, for each channel belonging to at least one second frequency band, the number of base stations in use indicating the number of other base stations that use the channel; and a noise level of the channel;
The used channel determining unit determines, as the second used channel, a channel that is different from the first used channel and has the smallest at least one of the number of used base stations, the load factor, and the noise level. do,
The base station according to claim 4 or 5. The used channel determination unit identifies the channel with the minimum load factor, and if there is only one identified channel with the minimum load factor, determines the identified one channel as the second used channel, If there are multiple channels with the identified minimum load factor, the channel with the minimum number of base stations in use is identified from among the channels with the minimum load factor, and the channel with the minimum number of base stations in use is identified. If there is only one channel, the specified one channel is determined as the second used channel, and if there are multiple channels with the minimum number of specified base stations in use, the plurality of channels with the minimum number of used base stations are determined. If there is only one channel with the minimum noise level, the identified one channel is determined to be the second channel to be used, and If there are multiple channels with the lowest noise level, one channel selected from the identified channels with the lowest noise level is determined to be the second used channel;
The base station according to claim 6. a detection determination unit that determines whether a radar wave is detected in either the first usage channel or the second usage channel;
further comprising a transmission control unit that controls transmission of the data frame to the first base station or the second base station based on the first used channel information and the second used channel information,
When it is determined that radar waves have been detected in either the first use channel or the second use channel, the transmission control section changes the channel on which it has been determined that the radar waves have been detected to a different channel. , controlling the data frame to be transmitted to the first base station or the second base station;
The base station according to any one of claims 1 to 7. The transmission control unit changes at least one of the first used channel and the second used channel to a channel belonging to the first frequency band, and when a preset carrier sense time elapses, the changed changing at least one of the first used channel and the second used channel to the channel determined by the used channel determining unit again;
The base station according to claim 8. The first frequency band is a 2.4GHz or 5GHz W52 band,
The second frequency band is a 5GHz W52 band, a 5GHz W53 band, a 5GHz W56 band, or a 6GHz band.
The base station according to claim 4. comprising a first base station, a second base station, and a third base station capable of communicating with the first base station and the second base station,
The first base station, the second base station, and the third base station each have:
It has a plurality of wireless modules that wirelessly communicate using channels belonging to one of a plurality of mutually different frequency bands,
The third base station is
a used channel information acquisition unit that acquires first used channel information indicating a first used channel used for transmitting and receiving data frames to and from the first base station transmitted from the first base station;
a usage channel determining unit that determines a channel different from the first usage channel as a second usage channel used for transmitting and receiving data frames to and from the second base station;
a used channel notification unit that transmits second used channel information indicating the determined second used channel to the second base station via one of the plurality of wireless modules;
Communications system. A communication method using a plurality of wireless modules that wirelessly communicate with a plurality of other base stations using channels belonging to one of a plurality of mutually different frequency bands,
First used channel information indicating a first used channel used for transmitting and receiving data frames to and from the first base station, which is transmitted from a preset first base station among the other plurality of base stations. and the steps to obtain
A channel different from the first used channel is used as a second used channel used for transmitting and receiving data frames with a second base station different from the first base station among the other plurality of base stations. Steps to decide;
transmitting second used channel information indicating the determined second used channel to the second base station via any of the plurality of wireless modules;
Communication method.

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