Wireless LAN device, channel control method, and program

Abstract

To reduce a time when radio waves are not transmitted at startup and achieve wireless communication using a wide bandwidth.SOLUTION: A wireless LAN device includes a communication unit that performs wireless communication with a wireless terminal, a receiving unit that is capable of receiving priority radio waves and monitors the priority radio waves, and a control unit that controls the operation of the communication unit and the receiving unit. The control unit, upon startup, causes the communication unit to start the wireless communication using an initial channel belonging to a first frequency band, which is a frequency band in which the priority radio waves do not exist, as a communication channel, and upon startup, causes the receiving unit to monitor the priority radio waves in a second frequency band, which is a frequency band in which the priority radio waves may exist, and if the receiving unit does not detect the priority radio waves on the first channel within the second frequency band for a predetermined period, switches the communication channel used by the communication unit from the initial channel to the first channel.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wireless LAN (Local Area Network) device, a channel control method, and a program. [Background technology]

[0002] In recent years, wireless LAN access points that enable communication using frequencies in the 5 GHz band have become widespread. The 5 GHz band refers to frequencies used in channels such as the W52, W53, and W56 bands. Generally, the W53 and W56 bands have a large number of channels, enabling wireless communication over a wide bandwidth. However, these bands are communication bands that contain priority radio waves such as radar waves, and it is mandatory to use a function called DFS (Dynamic Frequency Selection), which switches to another channel when radar waves are detected.

[0003] On the other hand, the W52 band does not require DFS, but only has four channels. Therefore, if many wireless communication devices use channels in the W52 band, interference with other wireless communication devices occurs, resulting in a decrease in communication quality. Therefore, it is desirable not to continue using channels in the W52 band. Normally, when using the W53 and W56 bands, a CAC (Channel Availability Check) process or the like is required to find an available channel that does not interfere with radar waves, and this process takes at least 60 seconds. Therefore, when changing a communication channel from a channel in the W52 band to a channel in the W53 or W56 band, communication is interrupted for at least 60 seconds. There is a technology that can shorten this time (see, for example, Patent Document 1).

[0004] According to the technology disclosed in Patent Document 1, "a wireless communication device includes a communication unit that performs wireless communication with a wireless terminal; a monitoring unit that monitors radar waves using a second channel; and a control unit that, when radar waves are detected using the first channel, if a predetermined period of monitoring of radar waves using the second channel has not elapsed, switches the channel used by the communication unit to a third channel for which radar wave monitoring is not requested, and continues monitoring of radar waves using the second channel; and if the monitoring unit does not detect radar waves using the second channel for the predetermined period, the control unit switches the channel used by the communication unit from the third channel to the second channel (abstract excerpt)." [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-159672 Summary of the Invention [Problem to be solved by the invention]

[0006] The following analysis has been carried out by the inventors of the present invention.

[0007] According to the technology disclosed in Patent Document 1, during communication, the first channel in the W53 band or W56 band is switched to the third channel in the W52 band, thereby realizing wireless communication using the wide band of the W53 band or W56 band without any downtime during communication.

[0008] However, when wireless communication is to be performed using a wide band using a channel in the W53 or W56 band, even if the technology disclosed in Patent Document 1 is used, the signal will be stopped for at least 60 seconds when the device is started up.

[0009] The present invention has been made in view of the above circumstances, and aims to provide a technology that reduces the blackout time at startup and contributes to realizing wireless communication using a wide bandwidth. [Means for solving the problem]

[0010] According to a first aspect of the present disclosure, a communication unit that performs wireless communication with a wireless terminal; a receiving unit capable of receiving a priority radio wave and monitoring the priority radio wave; There is provided a wireless LAN device including a control unit that controls the operations of the communication unit and the receiving unit. The control unit At the time of activation, the communication unit starts the wireless communication using an initial channel belonging to a first frequency band, which is a frequency band in which the priority radio wave does not exist, as a communication channel; At startup, the receiving unit is made to monitor the priority radio waves within a second frequency band, which is a frequency band in which the priority radio waves may exist, and if the receiving unit does not detect the priority radio waves on a first channel within the second frequency band for a predetermined period of time, the communication channel used by the communication unit is switched from the initial channel to the first channel.

[0011] According to a second aspect of the present disclosure, A channel control method is provided for a wireless LAN device that includes a communication unit that performs wireless communication with a wireless terminal, a receiving unit that is capable of receiving priority radio waves and monitors the priority radio waves, and a control unit that controls the operation of the communication unit and the receiving unit. The control unit At the time of startup, the communication unit starts the wireless communication using an initial channel belonging to a first frequency band, which is a frequency band in which the priority radio wave does not exist, as a communication channel, and the receiving unit monitors the priority radio wave within a second frequency band, which is a frequency band in which the priority radio wave may exist; When the receiving unit does not detect the priority radio wave for a predetermined period of time on a first channel within the second frequency band, the communication unit switches the communication channel used from the initial channel to the first channel.

[0012] According to a third aspect of the present invention, A computer of a wireless LAN device having a communication unit that performs wireless communication with a wireless terminal and a receiving unit that can receive and monitor priority radio waves. a step of, at the time of startup, causing the communication unit to start the wireless communication using an initial channel belonging to a first frequency band, which is a frequency band in which the priority radio wave does not exist, as a communication channel, and causing the receiving unit to monitor the priority radio wave within a second frequency band, which is a frequency band in which the priority radio wave may exist; A program is provided for executing a procedure in which, if the receiving unit does not detect the priority radio wave on a first channel within the second frequency band for a predetermined period of time, the communication channel used by the communication unit is switched from the initial channel to the first channel.

[0013] These programs can be recorded on a computer-readable storage medium. The storage medium can be a non-transitory medium such as a semiconductor memory, a hard disk, a magnetic recording medium, or an optical recording medium. The present invention can also be embodied as a computer program product. [Effects of the Invention]

[0014] According to the present invention, it is possible to suppress the downtime at startup and to realize wireless communication using a wide band. [Brief explanation of the drawings]

[0015] [Figure 1] 1A is an overall configuration diagram of an example of a communication system according to the present disclosure, and FIG. 1B is a functional block diagram of an example of a wireless LAN device according to the present disclosure. [Figure 2] 10 is a flowchart of an example of a channel control process at startup according to the present disclosure. [Figure 3] 1A is a functional block diagram of an example of an overall configuration of a communication system according to the present disclosure and an example of a wireless LAN device, and FIG. 1B is an explanatory diagram for explaining an example of a memory unit of a wireless LAN device according to the present disclosure. [Figure 4]FIG. 1 is an explanatory diagram for explaining the channel configuration of the 5 GHz band. [Figure 5] FIG. 1 is a diagram showing an example of channel switching according to the present disclosure in time series. [Figure 6] 10 is a flowchart of a startup channel control process for a receiving unit according to the present disclosure. [Figure 7] 10 is a flowchart of a channel control process at startup for a communication unit according to the present disclosure. [Figure 8] 2 is an explanatory diagram illustrating an example of a storage unit of a wireless LAN device according to the present disclosure; FIG. [Figure 9] FIG. 1 is a diagram showing an example of channel switching according to the present disclosure in time series. [Figure 10] 10 is a flowchart of a startup channel control process for a receiving unit according to the present disclosure. [Figure 11] 1 is a hardware configuration diagram illustrating an example of a hardware configuration of a wireless LAN device according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0016] An outline of one embodiment of the present invention (hereinafter referred to as the present embodiment) will be described below with reference to the drawings. Note that reference numerals in the drawings are assigned to each element for convenience as an example to facilitate understanding, and are not intended to limit the present invention to the illustrated form. Furthermore, connection lines between blocks in the drawings and the like referred to in the following description include both bidirectional and unidirectional lines. Unidirectional arrows are used to schematically indicate the flow of the main signal (data) and do not exclude bidirectionality.

[0017] In addition, although there are ports and interfaces at the connection points of input and output of each block in the figure, they are not shown. In the following explanation, "A and / or B" means either A or B, or A and B.

[0018] <<First Embodiment>> An overview of this embodiment will be described. In this embodiment, a wireless LAN (Local Area Network) device has a communication function using the 5 GHz band. Even if the wireless LAN device of this embodiment uses a channel in the W53 band or W56 band of the 5 GHz band as a communication channel for wireless communication with a wireless LAN client device, at startup, the wireless LAN device uses a channel in the W52 band as the communication channel to start wireless communication with the wireless LAN client device. At the same time, the wireless LAN device monitors each channel in the W53 band or W56 band in a predetermined order for priority radio waves, and if there is a channel determined to be free of interference with the priority radio waves, switches the communication channel with the wireless LAN client device to that channel.

[0019] Before describing the wireless LAN device that realizes this, the overall configuration of a communication system 900a of this embodiment will be described. Fig. 1(a) is an example of an overall configuration diagram of the communication system 900a of this embodiment. As shown in this diagram, the communication system 900a of this embodiment includes a wireless LAN device 100a and a wireless LAN slave device 300.

[0020] The wireless LAN device 100a communicates with a server device or the like via a public network such as the Internet 400, and relays communication between the wireless LAN slave device 300 and the Internet 400.

[0021] In this embodiment, the wireless LAN device 100a is, for example, a 5 GHz band wireless LAN access point. Therefore, the wireless LAN device 100a has a dynamic frequency selection function called DFS (Dynamic Frequency Selection) to avoid radio wave interference with radar waves, which are one of the priority radio waves. The radar waves are transmitted from a radar transmitter 500.

[0022] DFS includes functions such as a CAC (Channel Availability Check) function and an ISM (In Service Monitoring) function. CAC is a function that monitors a channel to be used as a communication channel for priority radio waves (radar waves) for one minute (60 seconds) before starting communication. If priority radio waves are not detected on the channel during that time, the wireless LAN device 100a can start wireless communication using that channel as the communication channel. ISM is a function that constantly monitors priority radio waves (radar waves) on a channel to be used during communication. If priority radio waves are detected during communication, the wireless LAN device 100a stops using that channel within 10 seconds. After stopping use of the channel, the wireless LAN device 100a monitors another channel for one minute (60 seconds), and if priority radio waves are not detected during that time, it switches the communication channel to that channel.

[0023] The wireless LAN slave device 300 is a wireless terminal (information processing device) capable of wireless communication in the 5 GHz communication band (frequency band), and in this embodiment, is connected to the Internet 400 via the wireless LAN device 100a.

[0024] The wireless LAN device 100a and the wireless LAN slave device 300 share the 5 GHz communication bands called the W53 band and the W56 band with the radar transmitter 500. The wireless LAN device 100a and the wireless LAN slave device 300 are required to give priority to radar waves (priority radio waves) transmitted and received by the radar transmitter 500.

[0025] 1B is an example of a functional block diagram of a wireless LAN device 100a according to this embodiment. As shown in this diagram, the wireless LAN device 100a according to this embodiment includes a communication unit 110a, a receiving unit 120a, and a control unit 130a.

[0026] The communication unit 110a performs wireless communication with the wireless LAN slave device 300 (wireless terminal). In this embodiment, as described above, the wireless communication is performed using a channel in any one of the 5 GHz bands, W52 band, W53 band, and W56 band, as a communication channel.

[0027] The receiver 120a is capable of receiving radar waves (priority radio waves) transmitted and received by the radar transmitter 500, and monitors the priority radio waves.

[0028] The control unit 130a controls the operations of the communication unit 110a and the receiving unit 120a. In this embodiment, particularly, the control unit 130a, at startup, causes the communication unit 110a to start wireless communication with the wireless LAN slave device 300 using an initial channel belonging to the W52 band, which is a frequency band (first frequency band) in which radar waves are not present, as the communication channel. Even if, for example, a channel in the W53 band or W56 band, which is a frequency band (second frequency band) in which radar waves may be present, is selected as the communication channel with the wireless LAN slave device 300, the control unit 130a, at startup, causes wireless communication to start using a channel belonging to the W52 band.

[0029] Furthermore, if the channel selected as the communication channel belongs to the W53 band or the W56 band (second frequency band), the control unit 130a, upon startup, causes the receiving unit 120a to monitor radar waves (priority radio waves) within the second frequency band. The receiving unit 120a monitors each channel of the W53 band or the W56 band (second frequency band) in a predetermined order for a predetermined period of time to determine whether radar waves are detected. Here, the predetermined period is, for example, 60 seconds, which is the period designated for performing CAC. If there is a channel (first channel) for which the receiving unit 120a does not detect priority radio waves within the predetermined period (60 seconds), the control unit 130a switches the communication channel used by the communication unit 110a from the initial channel to the first channel. The communication unit 110a performs wireless communication using the switched first channel.

[0030] [Startup channel control processing] Next, the flow of channel control processing at startup by the control unit 130a of the wireless LAN device 100a of this embodiment will be described. Figure 2 shows the processing flow of the channel control processing at startup of this embodiment. This processing is started when the wireless LAN device 100a is started.

[0031] It is assumed that the order in which priority radio waves are monitored (CAC is performed) for each channel in the W53 and W56 bands is predetermined. The channel for which CAC is performed nth is called the nth channel. n is a counter (an integer greater than or equal to 1 and less than or equal to the number of channels in the W53 and W56 bands). The period during which priority radio waves are monitored by CAC is called the CAC period. Specifically, it is 60 seconds.

[0032] First, the control unit 130a sets a channel in the W52 band (initial channel) as a communication channel for the communication unit 110a to wirelessly communicate with the wireless LAN slave device 300 (step S1101). The communication unit 110a starts wireless communication with the wireless LAN slave device 300 using this initial channel.

[0033] Next, the control unit 130a initializes a counter n (n=1) (step S1102), and sets the n-th channel in the W53 band and the W56 band to the receiving unit 120a (step S1103). The receiving unit 120a starts monitoring priority radio waves (radar waves) on the set channel.

[0034] The control unit 130a determines at predetermined time intervals (for example, every second) whether the CAC period has elapsed since step S1103 (step S1104). If the CAC period has not elapsed (S1104; No), the control unit 130a determines whether the receiving unit 120a has detected a priority radio wave (step S1105). If the receiving unit 120a has not detected a priority radio wave (S1105; No), the control unit 130a continues monitoring the priority radio wave.

[0035] On the other hand, if detected (S1105; Yes), the control unit 130a sets the next channel to be monitored in the receiving unit 120a (steps S1106, S1103) and starts monitoring the priority radio wave.

[0036] On the other hand, if the CAC period has elapsed without detecting a priority radio wave on the nth channel (S1104; Yes), the control unit 130a sets the nth channel to the communication unit 110a (step S1107). That is, the control unit 130a sets the channel as a channel that the communication unit 110a can use for wireless communication with the wireless LAN slave device 300. The communication unit 110a performs wireless communication with the wireless LAN slave device 300 using the set nth channel. This completes the channel control process at startup.

[0037] When counter n reaches the number of channels in the W53 and W56 bands, n is initialized again, and monitoring continues from the first channel. At this time, according to the DFS specifications, for a channel on which radar waves have been detected, 30 minutes must have passed since the detection. Therefore, in step S1107, it is determined not only whether the CAC period has elapsed, but also whether 30 minutes have passed since the previous priority radio wave detection timing.

[0038] As described above, in this embodiment, even if the W53 band and W56 band, which allow for the use of wide bandwidths, are selected as the communication channel with the wireless LAN slave device 300, the wireless LAN device 100a performs control at startup to first start wireless communication with the wireless LAN slave device 300 using a channel in the W52 band (initial channel) that does not require DFS. Then, while wireless communication with the wireless LAN slave device 300 is being performed using the initial channel, CAC is performed on channels in the W53 band and / or W56 band, an available channel is identified, and the communication channel used for wireless communication with the wireless LAN slave device 300 is switched from the initial channel to the identified available channel.

[0039] As a result, according to this embodiment, even at startup, wireless communication can be performed without a downtime by using a channel in the W52 band. During this time, the receiving unit 120a performs CAC, identifies an available channel, and switches from the initial channel to an available channel, so wireless communication is not performed using a channel in the W52 band for a long period of time. Therefore, wireless communication can be immediately performed using a channel in the W53 band or W56 band, which has less interference with other devices and allows the use of a wide band.

[0040] That is, according to this embodiment, it is possible to suppress the downtime at startup and realize wireless communication using a wide band.

[0041] <<Second embodiment>> Next, a second embodiment to which the present invention is applied will be described. This embodiment is an embodiment in which the first embodiment is embodied in more detail. In this embodiment, components with the same names as those in the first embodiment basically have the same functions as those in the first embodiment. Below, this embodiment will be described, focusing on the differences from the first embodiment.

[0042] 3(a), in the present embodiment, similarly to the first embodiment, a communication system 900 includes a wireless LAN device 100 and a wireless LAN slave device 300. The wireless LAN device 100 communicates with a server device or the like via a public network such as the Internet 400. The wireless LAN device 100 also relays communication between the wireless LAN slave device 300 and the Internet 400.

[0043] The wireless LAN device 100 is a wireless LAN access point having a communication function in the 5 GHz band, which includes the W52 band, the W53 band, and the W56 band, for example. Therefore, the wireless LAN device 100 has a DFS function to avoid radio wave interference with the radar waves transmitted and received by the radar transmitter 500.

[0044] 3(a), the wireless LAN device 100 of this embodiment includes a communication unit 110, a receiving unit 120, and a control unit 130. The wireless LAN device 100 of this embodiment further includes a WAN (Wide Area Network) interface (I / F) 150 and a LAN I / F 160. The control unit 130 also includes a storage unit 140.

[0045] The WAN I / F 150 connects to a WAN line. The wireless LAN device 100 connects to an external network such as the Internet 400 via the WAN line. The LAN I / F 160 connects to, for example, a wired LAN. The wireless LAN device 100 can connect to a terminal such as a user's PC (Personal Computer) 410 via the LAN I / F 160. Note that configurations with the same names as those in the first embodiment basically have the same functions as the functions with the same names in the first embodiment.

[0046] That is, the communication unit 110 performs wireless communication with the wireless LAN slave device 300 (wireless terminal). In this embodiment, as described above, communication is performed in any one of the bands W52, W53, and W56 in the 5 GHz band.

[0047] Specifically, the communication unit 110 uses the channel set by the control unit 130 as the communication channel to perform wireless communication with the wireless LAN slave device 300 .

[0048] The communication unit 110 of this embodiment has an auto channel select function that automatically selects a channel to be used for communication with the wireless LAN slave device 300. The auto channel select function is a function that automatically selects a channel that is not being used by other nearby wireless LAN devices at startup to avoid radio wave interference. Generally, the W56 band has the largest number of channels, so this band is often selected.

[0049] The receiving unit 120 detects radar waves transmitted and received by the radar transmitter 500. Specifically, if the channel set by the control unit 130 is the same as the channel used for the radar waves, the receiving unit 120 receives (detects) the radar waves transmitted from the radar transmitter 500. For example, when the receiving unit 120 detects radar waves, it notifies (interrupts) the control unit 130.

[0050] In FIG. 3(a), two radar transmitters 500 are shown as an example: radar transmitter 501 and radar transmitter 502. These transmitters emit radar waves of different frequencies. The number of radar transmitters 500 is not limited to this. Furthermore, the radar transmitter 500 is not limited to those provided in fixed buildings, such as weather radars. For example, the radar transmitter 500 may be provided in a mobile body such as a "maritime radio navigation," "mobile (excluding aeronautical mobile)," "earth exploration satellite (active)," "space research (active)," or "radiolocation."

[0051] The control unit 130 controls the operations of the communication unit 110 and the receiving unit 120. The control unit 130 sets channels for the communication unit 110 and the receiving unit 120. Specifically, the control unit 130 sets information specifying the channel (hereinafter also simply referred to as the channel) in a predetermined register of the storage unit 140, and controls the channel used by the communication unit 110 and the receiving unit 120. The communication unit 110 and the receiving unit 120 refer to the channel set in the register of the storage unit 140 and execute processing.

[0052] 3(b), the storage unit 140 includes a register TR201, a register R202, and a flag F storage area 203 that stores a flag F. In addition, the storage unit 140 includes storage areas that store various types of data required during processing.

[0053] Register TR201 is an area for storing channels used by communication unit 110. Register R202 is an area for storing channels used by receiving unit 120. Flag F storage area 203 is an area for setting flag F. In this embodiment, flag F is a flag that is set when receiving unit 120 performs CAC on a predetermined channel and does not detect radar waves within the CAC period (60 seconds). Details will be described later.

[0054] Even if a channel in the W53 band or the W56 band is selected by the above-mentioned auto channel select function at startup, the control unit 130 sets a channel in the W52 band as the initial channel for the communication channel of the communication unit 110. That is, the control unit 130 sets a channel in the W52 band in the register TR201.

[0055] At this time, the channel to be set as the initial channel is determined in advance or selected randomly.

[0056] Furthermore, at startup, the control unit 130 sets a channel in the W53 band or the W56 band in the receiving unit 120 in a predetermined order. That is, the control unit 130 sets a channel in the W53 band or the W56 band in the register R202. Then, while the receiving unit 120 is performing CAC, the control unit 130 sets the flag F to 0.

[0057] If the receiving unit 120 detects radar waves on the channel set in register R202 within a 60-second CAC period, the control unit 130 sets the next channel in register R202. If the receiving unit 120 does not detect radar waves on the channel set in register R202 within a 60-second CAC period, the control unit 130 sets flag F to 1. When flag F is set to 1, the control unit 130 sets the channel set in register R202 at that time in register TR201. In other words, the channel used by the communication unit 110 for communication with the wireless LAN slave device 300 is switched from the initial channel to the new channel.

[0058] For ease of explanation, hereinafter, setting information specifying a channel in register TR201 will also be simply referred to as setting a channel in communication unit 110. Similarly, setting information specifying a channel in register R202 will also be simply referred to as setting a channel in receiving unit 120.

[0059] Here, the channel configuration of the 5 GHz band will be explained using Figure 4. Figure 4 shows the channels of the W52 band, W53 band, and W56 band included in the 5 GHz band. As shown in this figure, the W52 band includes 36ch (channels), 40ch, 44ch, and 48ch. The W53 band includes 52ch, 56ch, 60ch, and 64ch. The W56 band includes 100ch, 104ch, 108ch, 112ch, 116ch, 120ch, 124ch, 128ch, 132ch, 136ch, 140ch, and 144ch.

[0060] As shown in the figure, in the 5 GHz band, each channel has a bandwidth of 20 MHz. The control unit 130 basically sets one of the channels with a bandwidth of 20 MHz to the communication unit 110 or the reception unit 120.

[0061] There is a technology called channel bonding, which uses (bundles) multiple channels simultaneously to expand bandwidth and increase communication volume and speed. Channels that can be bundled are limited to adjacent, contiguous channels. As shown in the diagram, at 5 GHz, channel widths of 40 MHz, 80 MHz, and 160 MHz are possible. A 40 MHz bandwidth is achieved by bundling two 20 MHz bandwidth channels. An 80 MHz bandwidth is achieved by bundling four 20 MHz bandwidth channels. A 160 MHz bandwidth is achieved by bundling eight 20 MHz bandwidth channels.

[0062] In this embodiment, the channels of the communication unit 110 and the receiving unit 120 may be set using such channel-bonded bandwidth. When setting to use channels of these bandwidths, the control unit 130 bundles adjacent, continuous channels as shown in the figure, treats them as a single channel, and sets it to the communication unit 110 or the receiving unit 120.

[0063] [Startup switching control] An outline of channel switching control by the control unit 130 at startup will be explained using a specific example. Figure 5 is an explanatory diagram for explaining the control by the control unit 130 of this embodiment. Here, the change (switching) of the channels set in the communication unit 110 and the receiving unit 120 after startup is shown in chronological order. The time at startup is assumed to be t0.

[0064] Here, it is assumed that the receiver 120 monitors radar waves in the order of 100ch in the W56 band, 116ch in the W56 band, and 52ch in the W53 band. It is also assumed that the radar waves of 100ch and 116ch are in use (transmitted from the radar transmitter 500). The CAC period is 60 seconds.

[0065] First, when the wireless LAN device 100 is started up, the control unit 130 sets, for example, 36ch in the W52 band as an initial channel for the communication unit 110. In this figure, (TRX) means the transmitting / receiving unit (communication unit 110). The communication unit 110 uses the set 36ch as the communication channel and starts wireless communication with the wireless LAN slave device 300.

[0066] At the same time, the control unit 130 sets the receiving unit 120 to 100ch in the W56 band and starts CAC. In this figure, (RX) refers to the receiving unit 120. When the receiving unit 120 detects a radar wave on 100ch at time t1, which is within 60 seconds from the start of CAC (startup: time t0), it notifies the control unit 130.

[0067] In response to this, control unit 130 switches the channel set in receiving unit 120 to channel 116 in the W56 band. Receiving unit 120 starts CAC on channel 116 from time t1. Then, when receiving unit 120 detects radar waves on channel 116 at time t2, which is within 60 seconds from time t1, it notifies control unit 130.

[0068] In response to this, control unit 130 switches the channel set in receiving unit 120 to channel 52 in the W53 band. Receiving unit 120 starts CAC on channel 52 from time t2.

[0069] If control unit 130 does not receive a radar wave detection notification from receiving unit 120 at time t3, 60 seconds after time t2, control unit 130 switches the channel set for communication unit 110 to channel 52 in the W53 band. After time t3, communication unit 110 communicates with wireless LAN slave device 300 on channel 52 in the W53 band.

[0070] At time t3, which is 60 seconds after time t2, the control unit 130 may switch the channel set in the receiving unit 120 to a channel (XXch; W53 or W56 band) that is designated to be monitored next after 52ch in the W53 band. The receiving unit 120 starts CAC on that channel from time t3.

[0071] [Startup channel control process] Next, the flow of channel control processing at startup in this embodiment will be described with reference to Fig. 6 and Fig. 7. Here, Fig. 6 shows the processing flow of this processing for the receiving unit 120, and Fig. 7 shows the processing flow of this processing for the communication unit 110. Both processes are started when the wireless LAN device 100 is started. Here, the channel control processing at startup refers to the processing up to the time when a channel in the W53 band or W56 band is initially set in the communication unit 110 after startup.

[0072] As in the first embodiment, the order of channels to be monitored is assumed to be predetermined. The nth (n is an integer equal to or greater than 1) channel to be monitored is called the nth channel. The channel stored in register R202 is called the monitored channel. The CAC timer is a timer that measures the CAC period (here, 60 seconds) of the monitored channel. The detection flag is a flag that is set when the receiver 120 detects radar waves on the monitored channel.

[0073] First, the startup channel control process for the receiving unit 120 will be described with reference to Fig. 6. First, the control unit 130 performs an initial process (step S2101). Here, the value of flag F is reset to 0. Also, the counter n is set to 1. Furthermore, the CAC timer is reset to 0.

[0074] The control unit 130 sets the n-th channel in the register R202 as the monitoring channel and allows the receiving unit 120 to receive (step S2102). For example, in the above example, 100ch in the W56 band is set as the monitoring channel the first time (when n=1). In response to this, the receiving unit 120 starts CAC. The control unit 130 also activates the CAC timer (step S2103). Thereafter, the receiving unit 120 continues monitoring, and if it detects radar waves on the monitoring channel, it performs interrupt processing to notify the control unit 130 of this.

[0075] The control unit 130 checks at predetermined time intervals whether 60 seconds have elapsed since the start of CAC on the monitoring channel (step S2104). If 60 seconds have not elapsed (S2104; No), the control unit 130 determines whether the receiving unit 120 has detected radar waves on the monitoring channel (step S2105). In other words, the control unit 130 determines whether there has been an interrupt from the receiving unit 120.

[0076] If an interrupt is received from the receiving unit 120 during the CAC period (S2105; Yes), the control unit 130 increments n by 1, resets the CAC timer to 0 (step S2106), and returns to step S2102. For example, in the above example, when n=2, 116ch in the W56 band is set as the monitoring channel.

[0077] On the other hand, if there is no interrupt during the CAC period (S2105; No), the control unit 130 returns to step S2104 and continues monitoring the monitored channel.

[0078] Furthermore, in step S2104, if 60 seconds have passed without radar wave detection (S2104; Yes), the control unit 130 sets flag F to 1 (step S2107) and ends the startup channel control process for the receiving unit 120.

[0079] In the startup channel control process for the receiver 120, it is not important to determine whether the CAC period has elapsed or whether radar waves have been detected first.

[0080] Next, the flow of the startup channel control process for the communication unit 110 will be described with reference to Fig. 7. In this process, the control unit 130 first sets a channel in the W52 band that does not require DFS in the register TR201, and permits the communication unit 110 to transmit and receive (communicate) (step S2201). In the above example, channel 36 in the W52 band is set. The communication unit 110 uses the set channel as the communication channel to perform wireless communication with the wireless LAN slave device 300.

[0081] Thereafter, the control unit 130 checks at predetermined time intervals whether the value set in the flag F is 1 (step S2202). If the value set in the flag F is not 1 (S2202; No), the control unit 130 returns to S2202 and repeats the checking process until the value set in the flag F becomes 1.

[0082] If the value set in flag F becomes 1 (S2202; Yes), control unit 130 sets in register TR201 the channel set in register R202 at that time, and permits communication unit 110 to communicate (step S2203). Then, the startup process for communication unit 110 ends.

[0083] As described above, this embodiment has the same configuration as the first embodiment, and therefore has the same effects as the first embodiment.

[0084] Generally, when the wireless LAN device 100 starts up and selects a channel in the W53 or W56 band as the communication channel, radar waves may be detected continuously on that channel within 60 seconds. In this case, radio waves will be stopped until the channel is switched to one where radar waves are not detected. For example, in the example described with reference to FIG. 5, since wireless communication in the 5 GHz band is unavailable during CAC after the device starts up, wireless communication in the 5 GHz band will be stopped for a maximum of approximately 180 seconds as the CAC period for the three channels, 100ch, 116ch, and 52ch.

[0085] However, according to the wireless LAN device 100 of this embodiment, even if a channel in the W53 band or W56 band is selected by the auto channel select function, at startup, a channel in the W52 band that does not require DFS is first selected, and wireless communication is performed with the wireless LAN slave device 300. Thereafter, when the receiver 120 completes CAC for the channel selected from the W53 band or W56 band, control is performed to switch to a channel in the same band where radar waves have not been detected. Therefore, immediately after startup, 5 GHz wireless communication can be performed without any interruption of radio waves.

[0086] As described above, according to this embodiment, in an area where one or more radar transmitters 500 using the W53 band and / or W56 band coexist, there is no blackout time due to CAC when the wireless LAN device 100 is started up. Furthermore, after a predetermined time, wireless communication with the wireless LAN slave device 300 is possible on a channel in the W53 band and / or W56 band for which CAC has been performed. This allows the user to achieve both short device startup blackout times and wireless communication on a wideband channel with less wireless interference with peripheral devices.

[0087] Furthermore, according to this embodiment, channels in the W53 band or the W56 band are set in the register R202 in a predetermined order and monitored by the receiving unit 120. In this case, the channel bandwidth is not limited. Therefore, channel-bonded channels of various bandwidths can be flexibly supported.

[0088] Therefore, according to this embodiment, it is possible to suppress the downtime at startup and realize wireless communication using a wide band.

[0089] <<Third Embodiment>> A third embodiment of the present invention will be described. In this embodiment, the CAC period is extended. The following description of this embodiment will focus on the configuration that differs from the second embodiment.

[0090] The configuration of the wireless LAN device 100 of this embodiment is basically the same as the configuration of the second embodiment shown in Fig. 3(a). However, in this embodiment, as shown in Fig. 8, the storage unit 140 includes the register TR201, register R202, and flag F storage area 203 for storing flag F, as well as an extension time storage area 204 for storing extension time T as a second predetermined time. Also, like the second embodiment, it includes storage areas for various data required during processing, such as counter n and CAC period.

[0091] The control unit 130 of this embodiment waits for the extension time T to elapse after the CAC period of 60 seconds has elapsed, and then sets the value of the flag F to 1.

[0092] [Startup switching control] Here, the operation of the control unit 130 of this embodiment will be described using a specific example. Figure 9 is an explanatory diagram for explaining the operation of the control unit 130 of this embodiment.

[0093] Here, as in the second embodiment, radar waves are monitored in the order of 100ch in the W56 band, 116ch in the W56 band, and 52ch in the W53 band. Also, radar waves on 100ch and 116ch are assumed to be in use. The CAC period is set to 60 seconds. The extension time is set to T.

[0094] First, when the wireless LAN device 100 is started up, the control unit 130 sets, as in the second embodiment, for example, 36ch in the W52 band as an initial channel for the communication unit 110. The communication unit 110 uses the set 36ch as the communication channel and starts wireless communication with the wireless LAN slave device 300.

[0095] At the same time, the control unit 130 sets the receiving unit 120 to 100ch in the W56 band and starts CAC. From then on, up to time t3, the process is the same as in the second embodiment described with reference to FIG. 5, and therefore a description thereof will be omitted here.

[0096] In the second embodiment, if no notification of radar wave detection is received from the receiver 120 at time t3, the controller 130 switches the channel set for the communication unit 110 to channel 52 in the W53 band. However, in this embodiment, the controller 130 waits an additional extension time T from time t3, and at time t4 (t3+T), switches the channel set for the communication unit 110 to channel 52 in the W53 band. After time t4, the communication unit 110 communicates with the wireless LAN slave device 300 on channel 52 in the W53 band.

[0097] At time t4, the control unit 130 may switch the channel set for the receiving unit 120 to a channel (XXch; W53 band or W56 band) that is determined to be monitored next after 52ch in the W53 band. The receiving unit 120 starts CAC on that channel.

[0098] [Startup channel control process] Next, the flow of the channel control process for the receiving unit 120 at startup of this embodiment will be described with reference to Fig. 10. The channel control process for the communication unit 110 at startup is the same as in the second embodiment, and therefore will not be described here. This process is also started when the wireless LAN device 100 is started.

[0099] The flow of this process is basically the same as that of the second embodiment, except that, while in step S2104 of the second embodiment, it is checked at predetermined time intervals whether 60 seconds have elapsed since the start of CAC on the monitoring channel, in this embodiment, it is checked at predetermined time intervals whether a period equal to 60 seconds plus the extension time T has elapsed (step S3104).

[0100] In this embodiment as well, in the startup channel control process for the receiver 120, it does not matter whether the determination of whether the CAC period has elapsed or the determination of whether radar waves have been detected is performed first.

[0101] As described above, this embodiment basically has the same configuration as the second embodiment, and therefore has the same effects as the second embodiment.

[0102] Furthermore, according to this embodiment, CAC of the monitoring channel is performed for a period of 60 seconds plus an additional extension time T. This makes it possible to reliably detect radar waves emitted by radar transmitters 500 that transmit radar waves at intervals of 60 seconds or more, thereby reducing the subsequent suspension period.

[0103] Therefore, according to this embodiment, it is possible to suppress the downtime at startup and realize wireless communication using a wide band.

[0104] <Variation 1> In the third embodiment, the method for setting the extension time T is not particularly limited. For example, the extension time T may be determined in advance and registered in the extension time storage area 204 of the storage unit 140. Alternatively, the user may set a desired value via, for example, an input / output interface (input unit) provided in the wireless LAN device 100 and store the value in the storage unit 140. Alternatively, various methods capable of storing the value in the storage unit 140 may be used, such as setting the value in the storage unit 140 from the PC 410 via the LAN I / F 160.

[0105] <Variation 2> Furthermore, in the above-described embodiments and modifications, the bandwidth of the channel set in the communication unit 110 is basically the same as the bandwidth of the channel monitored by the receiving unit 120, but this is not limitative. For example, the bandwidth of the channel monitored by the receiving unit 120 may be larger than the bandwidth of the channel set in the communication unit 110.

[0106] Specifically, when the communication unit 110 uses a channel with a width of 20 MHz, the receiving unit 120 may monitor a channel with a width of 40 MHz, 80 MHz, etc. In this case, the control unit 130 sets the desired 20 MHz channel for the communication unit 110 from among bands in which the receiving unit 120 did not detect radar waves during the CAC period (or after the extension time T has elapsed).

[0107] Furthermore, for example, the bandwidth of the channel monitored by the receiving unit 120 may be smaller than the bandwidth of the channel set by the communication unit 110.

[0108] <Variation 3> In addition, in each of the above-described embodiments and modifications, the order of channels monitored by the receiving unit 120 is predetermined. However, this is not limiting. For example, the channels selected by the auto channel select function of the communication unit 110 may be configured to be used as monitoring channels in order. In other words, rather than fixing the channel selection order, auto channel select is performed each time, and channels not used by nearby devices such as WiFi are given priority for monitoring.

[0109] Also, for example, if there is a known radar wave in use around the wireless LAN device 100, the channel of that radar wave may be excluded. Also, information on channels on which radar waves have been detected in the past may be stored in a storage device or the like of the wireless LAN device 100, and a channel on which radar has not been detected may be preferentially set as a monitoring channel.

[0110] <Variation 4> Furthermore, in each of the above-described embodiments and modifications, a receiver 120 dedicated to receiving radar waves is provided. However, this is not limiting. A plurality of communication units 110 may be provided, and the receiver 120 may not be provided. In this case, for example, at startup, one communication unit 110 is selected from the plurality of communication units 110, and the selected communication unit 110 monitors radar waves, and a channel in the W52 band is set for the other communication units 110, causing them to perform wireless communication with the wireless LAN slave device 300.

[0111] [Hardware configuration] Here, an example of the hardware configuration of the wireless LAN device 100 will be described. Fig. 11 is a diagram showing the hardware configuration of the wireless LAN device 100 of this embodiment.

[0112] The wireless LAN device 100 includes, for example, a CPU (Central Processing Unit) 131, a main storage device (memory) 141, an auxiliary storage device 142, a WAN port 151, a LAN port 161, an expansion port 170, transmission / reception circuits 111 to 114, a reception circuit 121, antennas 116 to 119, and an antenna 122, which are interconnected by an internal bus.

[0113] The CPU 131 realizes the above functions and comprehensively controls the entire device by, for example, loading a program stored in the auxiliary storage device 142 into the main storage device 141 and executing it. Note that the CPU 131 may be replaced by one or more processors such as an MPU (Micro Processing Unit).

[0114] The main storage device 141 is configured with a memory such as RAM (Random Access Memory), and serves as a work area when the CPU 131 processes programs and the like executed by the wireless LAN device 100. In each of the above embodiments, the main storage device 141 also functions as a storage unit 140 that stores various data calculated during processing. For example, the register TR201, the register R202, the flag F storage area 203, and the extension time storage area 204 may be provided in the main storage device 141. Furthermore, the counter n, the detection flag, and the like may also be stored in the main storage device 141.

[0115] The auxiliary storage device 142 is, for example, a read-only memory (ROM), a hard disk drive (HDD), or a solid state drive (SSD). The auxiliary storage device 142 stores various programs executed by the wireless LAN device 100. It may also store various data necessary for processing, such as a CAC period. The auxiliary storage device 142 may include a storage medium such as a flexible disk, a hard disk, an optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, or a DVD.

[0116] The programs stored in the auxiliary storage device 142 can be provided as a program product recorded on a non-transitory computer-readable recording medium. This storage medium can be a non-transitory medium such as a semiconductor memory, a hard disk, a magnetic recording medium, or an optical recording medium. That is, each embodiment and modification can also be embodied as a computer program product. The auxiliary storage device 142 can be used to store various programs recorded on a non-transitory computer-readable recording medium for the medium to long term.

[0117] The transmitting / receiving circuits 111 to 114, in combination with the antennas 116 to 119 connected thereto, perform wireless communication with the wireless LAN slave device 300 on the channel set in the register TR201. The transmitting / receiving circuits 111 to 114, for example, modulate data and transmit the modulated data to the wireless LAN slave device 300 via the antennas 116 to 119 connected thereto. The transmitting / receiving circuits 111 to 114 also demodulate the data received via the antennas 116 to 119 connected thereto.

[0118] In this embodiment, the sets of the respective transmission / reception circuits 111 to 114 and the antennas 116 to 119 connected thereto function as the communication unit 110 of each of the above-described embodiments under the control of the CPU 131. Note that, in this figure, the case where there are four sets of the transmission / reception circuits 111 to 114 and the antennas 116 to 119 connected thereto is illustrated, but the number is not limited to this.

[0119] In addition, the pairs of the respective transmission / reception circuits 111 to 114 and the antennas 116 to 119 connected thereto receive (detect) the radar waves transmitted from the radar transmitter 500 when the channel set as the communication channel is the same as the channel used for the radar waves.

[0120] The receiving circuit 121 and the antenna 122 connected thereto receive (detect) radar waves transmitted from the radar transmitter 500 on the channel set in the register R202. The receiving circuit 121 and the antenna 122 function as the receiving unit 120 in each of the above embodiments under the control of the CPU 131.

[0121] The WAN port 151 is a communication interface that connects to a WAN line. The LAN port 161 is a communication interface that connects to a LAN line. These function as the WAN I / F 150 and the LAN I / F 160, respectively, in the above-described embodiments under the control of the CPU 131.

[0122] The expansion port 170 is an interface for connecting a display device, an input device, etc. The display device is, for example, an LCD monitor. The input device is, for example, a device that accepts user operations, such as a keyboard or a mouse. For example, in a modification of the third embodiment, the extension time T may be set by the user using an input device connected to the expansion port 170.

[0123] It should be noted that the hardware configuration of the wireless LAN device 100 is not limited to this. For example, each function may be implemented using an integrated circuit (IC) dedicated to each process, an application specific integrated circuit (ASIC), a system on chip (SOC), a field programmable gate array (FPGA), or the like.

[0124] In the process flow used in the above explanation, multiple steps (processes) are described in order, but the order in which each step is performed is not limited to the order described. For example, the order of the steps shown in the figure can be changed to the extent that the content is not affected, such as performing each process in parallel.

[0125] Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified in various ways that would be understandable to those skilled in the art. Each embodiment and modification can be combined with other embodiments as appropriate. Furthermore, for example, the network configurations and element configurations shown in the drawings are examples intended to aid in understanding the present invention, and the present invention is not limited to the configurations shown in these drawings.

[0126] Finally, preferred embodiments of the present invention will be summarized below. Some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes. (Appendix 1) Wireless LAN devices are a communication unit that performs wireless communication with a wireless terminal; a receiving unit capable of receiving a priority radio wave and monitoring the priority radio wave; a control unit that controls operations of the communication unit and the receiving unit, The control unit At the time of activation, the communication unit starts the wireless communication using an initial channel belonging to a first frequency band, which is a frequency band in which the priority radio wave does not exist, as a communication channel; At startup, the receiving unit is made to monitor the priority radio waves within a second frequency band, which is a frequency band in which the priority radio waves may exist, and if the receiving unit does not detect the priority radio waves on a first channel within the second frequency band for a predetermined period of time, the communication channel used by the communication unit is switched from the initial channel to the first channel. (Appendix 2) 10. The wireless LAN device according to claim 1, It is desirable that the control unit switches the communication channel from the initial channel to the first channel immediately after the predetermined period has elapsed without detecting the priority radio wave on the first channel. (Appendix 3) 10. The wireless LAN device according to claim 1, It is desirable that the control unit waits for a second predetermined time to elapse after the predetermined time has elapsed without detecting the priority radio wave on the first channel, and then switches the communication channel from the initial channel to the first channel. (Appendix 4) 4. The wireless LAN device according to claim 3, further comprising an input unit, It is desirable that the second predetermined time period be set by the user via the input unit. (Appendix 5) 5. The wireless LAN device according to claim 1, The control unit monitors the priority radio waves using the channels in a predetermined order for each channel in the second frequency band; If the priority radio wave is detected on a predetermined channel during monitoring of the channel, it is desirable to start monitoring the priority radio wave using the next channel even if it is within the predetermined period. (Appendix 6) 6. The wireless LAN device according to claim 5, The control unit It is desirable that, at the timing when the communication channel used by the communication unit is switched to the first channel, the receiving unit starts monitoring the priority radio wave using the next channel. (Appendix 7) A channel control method by a control unit in a wireless LAN device including a communication unit that performs wireless communication with a wireless terminal, a receiving unit that can receive a priority radio wave and monitors the priority radio wave, and a control unit that controls operations of the communication unit and the receiving unit, comprising: At the time of startup, the communication unit starts the wireless communication using an initial channel belonging to a first frequency band, which is a frequency band in which the priority radio wave does not exist, as a communication channel, and the receiving unit monitors the priority radio wave within a second frequency band, which is a frequency band in which the priority radio wave may exist; When the receiving unit does not detect the priority radio wave for a predetermined period of time on a first channel within the second frequency band, the communication unit switches the communication channel used from the initial channel to the first channel. (Appendix 8) 8. The channel control method according to claim 7, It is preferable to wait for a second predetermined time to elapse after the predetermined time has elapsed without detecting the priority radio wave on the first channel, and then switch the communication channel from the initial channel to the first channel. (Appendix 9) The program is A computer of a wireless LAN device includes a communication unit that performs wireless communication with a wireless terminal and a receiving unit that can receive and monitors priority radio waves, a step of, at the time of startup, causing the communication unit to start the wireless communication using an initial channel belonging to a first frequency band, which is a frequency band in which the priority radio wave does not exist, as a communication channel, and causing the receiving unit to monitor the priority radio wave within a second frequency band, which is a frequency band in which the priority radio wave may exist; If the receiving unit does not detect the priority radio wave for a predetermined period of time on a first channel within the second frequency band, the receiving unit executes a procedure of switching the communication channel used by the communication unit from the initial channel to the first channel. (Appendix 10) In the program described in Appendix 9, It is preferable to wait for a second predetermined time to elapse after the predetermined time has elapsed without detecting the priority radio wave on the first channel, and then switch the communication channel from the initial channel to the first channel. (Appendix 11) In the wireless LAN device according to any one of Supplementary Notes 1 to 6, The priority radio wave is preferably a radar wave. Furthermore, it is desirable that the frequency bands in which the priority radio waves exist are the W53 and W56 bands of the 5 GHz band, and the frequency band in which the priority radio waves do not exist is the W52 band of the 5 GHz band. Furthermore, it is desirable that the predetermined period is 60 seconds. In addition, the forms of Supplementary Notes 7 and 9 can be expanded into the forms of Supplementary Notes 2, 4-6, just like Supplementary Note 1.

[0127] The disclosures of the above-mentioned patent documents, etc. are incorporated herein by reference. Modifications and adjustments of the embodiments and variations are possible within the scope of the entire disclosure of the present invention (including the scope of the claims), and further based on the basic technical concept thereof. Furthermore, various combinations and selections of the various disclosed elements (including each element of each claim, each element of each embodiment or variation, each element of each drawing, etc.) are possible within the scope of the disclosure of the present invention. In other words, the present invention naturally includes various modifications and alterations that would be possible by a person skilled in the art in accordance with the entire disclosure and technical concept, including the scope of the claims. In particular, with regard to the numerical ranges set forth herein, any numerical value or subrange included within the range should be construed as being specifically set forth, even if not otherwise specified. [Explanation of symbols]

[0128] 100: wireless LAN device, 100a: wireless LAN device, 110: communication unit, 110a: communication unit, 111: transmitting / receiving circuit, 112: transmitting / receiving circuit, 113: transmitting / receiving circuit, 114: transmitting / receiving circuit, 116: antenna, 117: antenna, 118: antenna, 119: antenna, 120: receiving unit, 120a: receiving unit, 121: receiving circuit, 122: antenna, 130: control unit, 130a: control unit, 131: CPU, 140: storage unit, 141: main storage device, 142: auxiliary storage device, 150: WAN I / F, 151: WAN port, 160: LAN I / F, 161: LAN port, 170: expansion port, 201: Register TR, 202: Register R, 203: Flag F storage area, 204: Extension time storage area, 300: Wireless LAN adapter, 400: Internet, 410: PC, 500: radar transmitter, 501: radar transmitter, 502: radar transmitter, 900: communication system, 900a: communication system

Claims

1. a communication unit that performs wireless communication with a wireless terminal; a receiving unit capable of receiving a priority radio wave and monitoring the priority radio wave; a control unit that controls operations of the communication unit and the receiving unit, The control unit At the time of activation, the communication unit starts the wireless communication using an initial channel belonging to a first frequency band, which is a frequency band in which the priority radio wave does not exist, as a communication channel; A wireless LAN device that, upon startup, causes the receiving unit to monitor the priority radio waves within a second frequency band, which is a frequency band in which the priority radio waves may exist, and if the receiving unit does not detect the priority radio waves on a first channel within the second frequency band for a predetermined period of time, switches the communication channel used by the communication unit from the initial channel to the first channel.

2. 2. The wireless LAN device according to claim 1, The control unit switches the communication channel from the initial channel to the first channel immediately after the predetermined period has elapsed without detecting the priority radio wave on the first channel.

3. 2. The wireless LAN device according to claim 1, The control unit waits for a second predetermined time to elapse after the predetermined time has elapsed without detecting the priority radio wave on the first channel, and then switches the communication channel from the initial channel to the first channel.

4. 4. The wireless LAN device according to claim 3, further comprising an input unit; The second predetermined time period is set by a user via the input unit.

5. 2. The wireless LAN device according to claim 1, The control unit monitors the priority radio waves using the channels in a predetermined order for each channel in the second frequency band; When the priority radio wave is detected on a predetermined channel during monitoring of the channel, the wireless LAN device starts monitoring the priority radio wave using the next channel even if the predetermined period is still in progress.

6. 6. The wireless LAN device according to claim 5, The control unit The wireless LAN device causes the receiving unit to start monitoring the priority radio waves using the next channel at the timing when the communication channel used by the communication unit is switched to the first channel.

7. A channel control method by a control unit in a wireless LAN device including a communication unit that performs wireless communication with a wireless terminal, a receiving unit that is capable of receiving a priority radio wave and monitors the priority radio wave, and a control unit that controls operations of the communication unit and the receiving unit, At the time of startup, the communication unit starts the wireless communication using an initial channel belonging to a first frequency band, which is a frequency band in which the priority radio wave does not exist, as a communication channel, and the receiving unit monitors the priority radio wave within a second frequency band, which is a frequency band in which the priority radio wave may exist; A channel control method in which, if the receiving unit does not detect the priority radio wave on a first channel within the second frequency band for a predetermined period of time, the communication channel used by the communication unit is switched from the initial channel to the first channel.

8. 8. A channel control method according to claim 7, comprising: A channel control method, wherein after the predetermined time has elapsed without detecting the priority radio wave on the first channel, a second predetermined time has elapsed, and the communication channel is switched from the initial channel to the first channel.

9. A computer of a wireless LAN device includes a communication unit that performs wireless communication with a wireless terminal, and a receiving unit that can receive a priority radio wave and monitors the priority radio wave, a step of, at the time of startup, causing the communication unit to start the wireless communication using an initial channel belonging to a first frequency band, which is a frequency band in which the priority radio wave does not exist, as a communication channel, and causing the receiving unit to monitor the priority radio wave within a second frequency band, which is a frequency band in which the priority radio wave may exist; and a program for executing a procedure for switching the communication channel used by the communication unit from the initial channel to the first channel when the receiving unit does not detect the priority radio wave on a first channel within the second frequency band for a predetermined period of time.

10. 10. The program according to claim 9, a program for waiting for a second predetermined time to elapse after the predetermined time has elapsed without detecting the priority radio wave on the first channel, and then switching the communication channel from the initial channel to the first channel;

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