Wireless communication device, wireless communication method, and wireless communication program

Abstract

To provide a wireless communication device capable of preventing or eliminating radio wave interference at an early stage.SOLUTION: A wireless communication device includes an AP communication module, an STA communication module, and a management unit. The AP communication module functions as an access point for wireless communication. The STA communication module is separate from an AP module and functions as a station for wireless communication. The management unit manages the AP communication module and the STA communication module. The STA communication module notifies the management unit of the channel determined to be used for wireless communication. The management unit performs a channel change process to cause the AP communication module to use a channel different from the channel received from the STA communication module.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a wireless communication device, and more particularly to a process for changing a channel used in wireless communication to prevent radio wave interference. [Background technology]

[0002] Patent Document 1 describes CSA (Channel Switch Announcement) as a technology for changing the channel used in wireless communication. CSA is a signal transmitted from an access point to a station when changing the channel used in wireless communication. In Patent Document 1, when radio wave interference is detected on the currently used channel, it is determined whether or not to change the channel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-148279 Summary of the Invention [Problem to be solved by the invention]

[0004] In the method of Patent Document 1, the channel used for wireless communication is changed after radio wave interference is detected, so there is a possibility that the period during which the device is affected by radio wave interference may become longer.

[0005] The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a wireless communication device that can eliminate radio wave interference before it occurs or at an early stage.

[0006] The problem to be solved by the present invention is as described above. Next, the means for solving this problem and the effects thereof will be explained.

[0007] According to a first aspect of the present invention, there is provided a wireless communication device having the following configuration: That is, the wireless communication device includes an AP communication module, a STA communication module, and a management unit. The AP communication module functions as an access point for wireless communication. The STA communication module is separate from the AP module and functions as a station for wireless communication. The management unit manages the AP communication module and the STA communication module. The STA communication module notifies the management unit of a channel determined to be used for wireless communication. The management unit performs a channel change process to cause the AP communication module to use a channel different from the channel received from the STA communication module.

[0008] This makes it less likely that the channels used by the AP communication module and the STA communication module will overlap, making it less likely that radio interference will occur. In particular, because the channel is received from the STA communication module, the channel can be changed earlier, allowing for earlier resolution of radio interference before it occurs, compared to changing the channel after detecting radio interference.

[0009] In the wireless communication device, it is preferable that the STA communication module notifies the management unit of the channel determined to be used in the wireless communication before starting the wireless communication.

[0010] This shortens the period during which radio interference occurs compared to when the channel is notified after wireless communication has started.

[0011] The wireless communication device preferably has the following configuration: the management unit stores the channel used by the AP communication module for wireless communication; the management unit compares the channel received from the STA communication module with the channel used by the AP communication module for wireless communication, and if it determines that the two are the same or that the two satisfy a similarity condition, it instructs the AP communication module to change the channel used for wireless communication.

[0012] This reduces the time required for comparison compared to obtaining the channel from the AP communication module each time a channel comparison is performed. Also, if it is determined that the approximate condition is met, the AP communication module's channel will be changed even if the channels are close to each other, further reducing radio interference.

[0013] The wireless communication device preferably has the following configuration: the AP communication module is capable of wireless communication in multiple frequency bands; the STA communication module is capable of wireless communication in multiple frequency bands; and the management unit performs the channel change process when the frequency band used by the AP communication module for wireless communication is the same as the frequency band used by the STA communication module for wireless communication.

[0014] Being able to support multiple frequency bands allows the wireless communication device to be compatible with a variety of environments and devices, and even when the AP communication module and the STA communication module use the same frequency band, they can use different channels.

[0015] According to a second aspect of the present invention, there is provided the following wireless communication method. That is, the wireless communication method uses an AP communication module that functions as a wireless communication access point and a STA communication module that is separate from the AP module and functions as a wireless communication station. The wireless communication method includes a first step and a second step. In the first step, a channel determined to be used in wireless communication with the STA communication module is identified. In the second step, the AP communication module is made to use a channel different from the channel identified in the first step.

[0016] According to a third aspect of the present invention, there is provided the following wireless communication program. That is, the wireless communication program is a program for controlling an AP communication module having a function as an access point for wireless communication and an STA communication module that is separate from the AP module and has a function as a station for wireless communication, and causes a computer to perform the following first and second steps. In the first step, a channel determined to be used in wireless communication with the STA communication module is identified. In the second step, the AP communication module is caused to use a channel different from the channel identified in the first step. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a block diagram of a wireless communication device and peripheral devices according to an embodiment of the present invention; [Figure 2] 10 is a flowchart of an AP communication module, a STA communication module, and a management unit. [Figure 3] A diagram showing the channels used for each wireless communication when the connection destination of the STA communication module is the first AP device, and the channels used for each wireless communication when the connection destination of the STA communication module is switched to the second AP device. DETAILED DESCRIPTION OF THE INVENTION

[0018] Next, an embodiment of the present invention will be described with reference to the drawings. First, a wireless communication device 1 and its surrounding communication environment will be described with reference to FIG.

[0019] The wireless communication device 1 is placed, for example, in a factory, a warehouse, an office, etc. As will be described later, the wireless communication device 1 simultaneously functions as an access point (wireless master device) and a station (wireless slave device). As a result, the wireless communication device 1 provides a wireless communication environment to surrounding STA devices 32, and communicates using a wireless communication environment provided by surrounding AP devices 31. The AP device 31 is a device that functions as a wireless communication access point (wireless master device), and the STA device 32 is a device that functions as a station (wireless slave device).

[0020] The wireless communication device 1 is used, for example, for collecting data. The wireless communication device 1 of this embodiment is installed on an automatic conveyance device 20 and is mobile. The wireless communication device 1 moves, for example, within a factory, and collects work data and sensor data from the STA device 32. The wireless communication device 1 transmits the collected work data and sensor data to the AP device 31. Note that the data transmitted and received by the wireless communication device 1 is an example and is not limited to work data and sensor data. The wireless communication device 1 may also be used as a repeater that relays communication between the STA device 32 and the AP device 31.

[0021] As shown in FIG. 1, the wireless communication device 1 includes a housing 10, an AP communication module 11, an STA communication module 12, an antenna 13, and a management unit 14.

[0022] The housing 10 is a box-shaped member that houses the AP communication module 11, the STA communication module 12, and the management unit 14. The housing 10 is not an essential component and can be omitted.

[0023] The AP communication module 11 is a communication module that functions as an access point for wireless communication. The AP communication module 11 establishes a wireless LAN network and performs wireless communication with one or more surrounding station devices (hereinafter, STA devices 32). A possible wireless communication standard is, for example, IEEE802.11, but this is not limiting. The AP communication module 11 of this embodiment supports multiple frequency bands (e.g., the 2.4 GHz band and the 5 GHz band) and communicates with the STA devices 32 using predetermined channels in these frequency bands. Note that the AP communication module 11 may support only one frequency band. The AP communication module 11 can perform wireless communication using a channel determined by itself or the management unit 14, and can also change the channel.

[0024] The STA communication module 12 is a communication module that functions as a wireless communication station. The STA communication module 12 performs wireless communication with a nearby access point device (hereinafter, AP device 31) via a wireless LAN network established by the AP device 31. As with the AP communication module 11, the wireless communication standard may be IEEE802.11, but is not limited to this. The STA communication module 12 also supports multiple frequency bands (for example, the 2.4 GHz band and the 5 GHz band). Note that the STA communication module 12 may support only one frequency band. Since the STA communication module 12 uses the wireless LAN network established by the AP device 31, it is generally unable to specify a frequency band or channel.

[0025] The wireless communication device 1 of this embodiment is configured to include one AP communication module 11 and one STA communication module 12, but may include multiple modules of at least one of them. In this embodiment, the AP communication module 11 and the STA communication module 12 are mounted on the same board, but they may also be mounted on different boards. However, since the AP communication module 11 and the STA communication module 12 are handled as a set, it is preferable that they be housed in a common housing 10, for example, so that they can be moved together.

[0026] The antennas 13 are provided on the outer surface of the housing. The wireless communication device 1 includes a plurality of antennas 13. Some of the antennas 13 are connected to the AP communication module 11 via signal lines, and transmit signals output by the AP communication module 11 to the STA device 32, or receive signals transmitted by the STA device 32 and output them to the AP communication module 11. Some of the antennas 13 are connected to the STA communication module 12 via signal lines, and transmit signals output by the STA communication module 12 to the AP device 31, or receive signals transmitted by the AP device 31 and output them to the STA communication module 12. The antennas 13 may be disposed inside the housing, or may be directly attached to the above-mentioned board.

[0027] The management unit 14 is realized by a CPU mounted on the above-mentioned board. The CPU executes a program stored in a storage device (not shown) to control the wireless communication device 1 as the management unit 14. The management unit 14 can communicate with the AP communication module 11 and the STA communication module 12 via a circuit mounted on the board. The management unit 14 may be mounted on a board different from that on which the AP communication module 11 and the STA communication module 12 are mounted. In this case, the AP communication module 11 and the management unit 14, and the STA communication module 12 and the management unit 14 are connected via electric wires or the like. The management unit 14 manages the communication status of the wireless communication device 1 and performs a channel change process, which will be described later. However, the management unit 14 may be a dedicated part for performing the channel change process.

[0028] Next, a process for suppressing radio interference will be described with reference to Figures 2 and 3. The following process is a wireless communication method performed by executing a wireless communication program.

[0029] First, we will explain radio wave interference that may occur in the wireless communication device 1 of this embodiment. As described above, the wireless communication device 1 includes an AP communication module 11 and a STA communication module 12, which independently communicate wirelessly. Furthermore, because the wireless communication device 1 is installed on an automated guided vehicle 20, the wireless communication environment changes constantly. In particular, the frequency band and wireless channel used by the STA communication module 12 for communication are determined by the external AP device 31 and cannot be determined by the device itself. As a result, the frequency band and channel used by the AP communication module 11 and the frequency band and channel used by the STA communication module 12 may overlap or coexist in a range that satisfies the similarity condition. In this case, the AP communication module 11 and the STA communication module 12 may be located close to each other, causing radio wave interference between them and degrading communication quality. Furthermore, even if the wireless communication device 1 is not installed on an automated guided vehicle 20, the above-mentioned radio wave interference may occur if the AP device 31 and the STA device 32 move or the wireless communication environment provided by the AP device 31 changes. That is, the wireless communication device 1 being installed on a moving body is just an example, and the position of the wireless communication device 1 may be fixed.

[0030] The following describes the processing performed by each device after starting the AP communication module 11, the STA communication module 12, and the management unit 14. The flowchart shown in Fig. 2 shows processing related to one of multiple frequency bands, and when multiple frequency bands are used, similar processing is performed for each frequency band.

[0031] After the AP communication module 11 performs a startup process (S101), it determines (S102) a channel to be used for communication with the STA device 32. The AP communication module 11 notifies the management unit 14 of the determined channel (S103).

[0032] After the startup process (S301), the STA communication module 12 scans and detects surrounding AP devices 31 (S302). The STA communication module 12 determines the AP device 31 to connect to, for example, based on radio wave strength or the like (S303). The STA communication module 12 identifies the channel used by the AP device 31 to connect to. The STA communication module 12 notifies the management unit 14 of the channel to be used in wireless communication with the AP device 31 (S304, first process, first step). Thereafter, the STA communication module 12 connects to the AP device 31 (S305).

[0033] After the startup process (S201), the management unit 14 receives the channel used by the AP communication module 11 (S202). This process corresponds to the process of step S103 by the AP communication module 11. The management unit 14 further receives the channel used by the STA communication module 12 (S203, first step). This process corresponds to the process of step S304 by the STA communication module 12.

[0034] Next, the management unit 14 determines whether the two channels (the channel used by the AP communication module 11 and the channel used by the STA communication module 12) are the same or similar (S204). If the two channels are the same, the above-mentioned radio interference will occur. Furthermore, even if the two channels are different, if the channels are similar (for example, if the difference in the number of channels is small, such as 1ch and 2ch), radio interference may occur. Whether the channels are similar or not is determined based on whether the approximation condition is met. For example, in the 2.4GHz band, it is preferable to separate the channels by five or more. Therefore, it is set that the approximation condition is met if the difference in the number of channels is four or less. The approximation condition is set in advance and stored in a storage device provided in the wireless communication device 1. Note that the process using the approximation condition is just an example and can be omitted.

[0035] If the management unit 14 determines that the two channels are the same or similar, it instructs the AP communication module 11 to change the channel to be used (S205, second process, second step). As described above, the STA communication module 12 cannot change the channel to be used by itself, so this instruction must be given to the AP communication module 11. The management unit 14 identifies a channel that is different from the channel used by the STA communication module 12 and is not similar to the channel used by the STA communication module 12, and transmits that channel to the AP communication module 11. The processing of steps S204 and S205 is collectively referred to as "channel change processing."

[0036] Other conditions may be taken into consideration when specifying the channel to be used by the AP communication module 11. For example, channels used by surrounding devices may be identified by scanning, and a channel different from those channels may be specified. Alternatively, if the wireless communication device 1 includes multiple AP communication modules 11 or STA communication modules 12, a channel not used by those modules may be specified.

[0037] After notifying the management unit 14 of the channel to be used in step S103, the AP communication module 11 waits for an instruction to change the channel while performing wireless communication with the STA device 32 (S104). When the AP communication module 11 receives an instruction to change the channel from the management unit 14, it changes the channel to be used in wireless communication to the channel instructed by the management unit 14 (S105). Thereafter, the AP communication module 11 transmits a CSA to the STA device 32 with which it is communicating to notify it of the channel change (S106). Then, after executing step S106, the AP communication module 11 executes step S104 and repeats the series of processes. Note that, as shown in FIG. 2, in this embodiment, the management unit 14 instructs the AP communication module 11 of the channel to be used in step S205. Therefore, it is not necessary to receive notification of the channel to be used again from the AP communication module 11 (that is, it is not necessary to execute step S103). Of course, the AP communication module 11 may execute step S103 after executing step S106.

[0038] Thereafter, for example, if the AP device 31 to which the STA communication module 12 is connected changes due to a change in the communication environment, and as a result the frequency band or channel used by the STA communication module 12 for wireless communication changes, the above-mentioned processing is performed again.

[0039] The management unit 14 does not have to specify the new channel. In this case, the management unit 14 notifies the AP communication module 11 that the channel needs to be changed and the channel to be used by the STA communication module 12. Instead of transmitting the CSA, the AP communication module 11 may disconnect all wireless communications with the STA device 32 and establish a new wireless connection using the new channel.

[0040] In this embodiment, the STA communication module 12 notifies the AP device 31 of the channel in step S304, and then connects to the AP device 31 in step S305. This allows the STA communication module 12 to notify the channel earlier than when the STA communication module 12 notifies the AP device 31 of the channel after connecting to the AP device 31, thereby shortening the period during which radio interference occurs. On the other hand, the STA communication module 12 may notify the AP device 31 of the channel after connecting to the AP device 31.

[0041] By performing the above processing, radio wave interference can be eliminated before it occurs or at an early stage. The advantages of the channel change processing of this embodiment will be specifically described below with reference to Fig. 3. In the following description, a first AP device 31a and a second AP device 31b are used as the AP device 31. The first AP device 31a and the second AP device 31b use different channels for communication.

[0042] In the situation shown in the upper diagram of Figure 3, the AP communication module 11 is communicating wirelessly with the STA device 32 on channel 11. Meanwhile, the STA communication module 12 is communicating wirelessly with the first AP device 31a on channel 1. Therefore, no radio wave interference occurs. Suppose that the wireless communication device 1 then moves closer to the second AP device 31b. Furthermore, the channel used by the second AP device 31b for wireless communication is channel 11.

[0043] If the radio wave environment of the first AP device 31a deteriorates as a result of the wireless communication device 1 moving, the STA communication module 12 will connect to the second AP device 31b. If the processing of this embodiment is not performed, the wireless communication of the AP communication module 11 and the wireless communication of the STA communication module 12 will both be on channel 11, causing radio wave interference. Furthermore, even if there is a function to change the channel after detecting radio wave interference, it may take a long time for the radio wave interference to actually be resolved.

[0044] In contrast, in this embodiment, before connecting to the second AP device 31b, the STA communication module 12 notifies the management unit 14 of the channel (ch11) to be used for wireless communication with the second AP device 31b. This makes it possible to detect at an early stage that radio wave interference will occur in the future. Furthermore, the management unit 14 instructs the AP communication module 11 to change the channel, so that radio wave interference can be resolved before it occurs or at an early stage, as shown in the lower diagram of FIG. 3.

[0045] As described above, the wireless communication device 1 of the above embodiment includes an AP communication module 11, an STA communication module 12, and a management unit 14. The wireless communication device 1 or the management unit 14, which corresponds to a computer, executes a wireless communication program to perform the following wireless communication method. The AP communication module 11 functions as an access point for wireless communication. The STA communication module 12 is separate from the AP module and functions as a station for wireless communication. The management unit 14 manages the AP communication module 11 and the STA communication module 12. The STA communication module 12 notifies the management unit 14 of the channel determined to be used for wireless communication. The management unit 14 performs channel change processing to cause the AP communication module 11 to use a channel different from the channel received from the STA communication module 12.

[0046] This makes it less likely that radio wave interference will occur, since the channels used by the AP communication module 11 and the STA communication module 12 are unlikely to overlap. In particular, since the channel is received from the STA communication module 12, the channel can be changed earlier, and radio wave interference can be eliminated before it occurs or at an earlier stage, compared to when the channel is changed after radio wave interference is detected.

[0047] In the wireless communication device 1 of the above embodiment, before starting wireless communication, the STA communication module 12 notifies the management unit 14 of the channel that has been determined to be used in the wireless communication.

[0048] This shortens the period during which radio interference occurs compared to when the channel is notified after wireless communication has started.

[0049] In the wireless communication device 1 of the above embodiment, the management unit 14 stores the channel used for wireless communication by the AP communication module 11. The management unit 14 compares the channel received from the STA communication module 12 with the channel used for wireless communication by the AP communication module 11, and if the management unit 14 determines that the two are the same or that the two satisfy an approximate condition, it instructs the AP communication module 11 to change the channel used for wireless communication.

[0050] This reduces the time required for comparison compared to when the channel is obtained from the AP communication module 11 each time a channel comparison is performed. Also, if it is determined that the approximation condition is met, the channel of the AP communication module 11 is changed even when the channels are close to each other, for example, so that radio interference can be further reduced.

[0051] In the wireless communication device 1 of the above embodiment, the AP communication module 11 is capable of wireless communication in multiple frequency bands. The STA communication module 12 is capable of wireless communication in multiple frequency bands. The management unit 14 performs channel change processing when the frequency band used by the AP communication module 11 for wireless communication and the frequency band used by the STA communication module 12 for wireless communication are the same.

[0052] Being able to support multiple frequency bands allows the wireless communication device 1 to be compatible with various environments and devices, and even when the AP communication module 11 and the STA communication module 12 use the same frequency band, they can use different channels.

[0053] The preferred embodiment of the present invention has been described above, but the above configuration can be modified, for example, as follows. Each modification may be made alone, or multiple modifications may be made in any combination.

[0054] A control device that is provided in the AP communication module 11 or the STA communication module 12 and controls communication may perform at least part of the processing of the management unit 14 in the above embodiment.

[0055] The flowcharts shown in the above embodiments are merely examples, and some processes may be omitted, some processes may be changed, or new processes may be added. For example, the process of step S102 may be omitted, and the management unit 14 may specify the initial channel. Also, instead of the process in which the AP communication module 11 or the STA communication module 12 transmits the channel to the management unit 14, the management unit 14 may inquire about the channel, and the AP communication module 11 or the STA communication module 12 may respond. [Explanation of symbols]

[0056] 1. Wireless communication device 11 AP Module 12 STA communication module 14 Management Department

Claims

1. an AP communication module having a function as an access point for wireless communication; an STA communication module that is separate from the AP module and has a function as a station for wireless communication; a management unit that manages the AP communication module and the STA communication module; Equipped with the STA communication module notifies the management unit of the channel determined to be used in wireless communication; The wireless communication device is characterized in that the management unit performs a channel change process to cause the AP communication module to use a channel different from the channel received from the STA communication module.

2. 2. The wireless communication device according to claim 1, The wireless communication device is characterized in that the STA communication module notifies the management unit of a channel determined to be used in the wireless communication before starting the wireless communication.

3. 2. The wireless communication device according to claim 1, the management unit stores a channel used by the AP communication module for wireless communication; A wireless communication device characterized in that the management unit compares the channel received from the STA communication module with the channel used by the AP communication module for wireless communication, and if it determines that the two are the same or that the two satisfy approximate conditions, it instructs the AP communication module to change the channel used for wireless communication.

4. 2. The wireless communication device according to claim 1, the AP communication module is capable of wireless communication in a plurality of frequency bands; the STA communication module is capable of wireless communication in a plurality of frequency bands; A wireless communication device characterized in that the management unit performs the channel change processing when the frequency band used by the AP communication module for wireless communication is the same as the frequency band used by the STA communication module for wireless communication.

5. A wireless communication method using an AP communication module having a function as an access point for wireless communication and an STA communication module that is separate from the AP module and has a function as a station for wireless communication, comprising: a first step of identifying a channel determined to be used in wireless communication with the STA communication module; a second step of causing the AP communication module to use a channel different from the channel identified in the first step; A wireless communication method comprising:

6. A wireless communication program for controlling an AP communication module having a function as an access point for wireless communication and an STA communication module that is separate from the AP module and has a function as a station for wireless communication, a first step of identifying a channel determined to be used in wireless communication with the STA communication module; a second step of causing the AP communication module to use a channel different from the channel identified in the first step; A wireless communication program that causes a computer to execute the above.

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