Radio base station, channel setting method, and program

Abstract

To automatically select a channel to be used for wireless communication.SOLUTION: A radio base station 103 includes: a communication unit 302 that searches for other radio base stations using a search frame and transmits a channel response frame that reports an operating channel in response to a search frame from another radio base station; a determination unit 304 that determines the presence or absence of another radio base station; and a processing unit 305 that determines an operating channel used by its own device to communicate with a wireless terminal. After the processing unit 305 tentatively determines the operating channel, the determination unit 304 determines whether the other radio base station exists.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a radio base station, a channel setting method, and a program therefor.

Background Art

[0002] Conventionally, as disclosed in Patent Document 1, radio base stations compliant with the IEEE802.11 standard have an automatic channel selection function called ACS (Automatic Channel Selection). When the radio base station is activated, it searches for and determines the operation channel with the least interference in the surrounding radio environment. ACS is used to suppress radio wave interference by automatically selecting the optimal operation channel according to the radio environment where the radio base station is installed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, if multiple radio base stations equipped with ACS are powered on simultaneously, and their startup timings overlap, a problem arises where the channels selected by ACS conflict among the multiple radio base stations. In this way, when multiple radio base stations exist in a communication system, if each radio base station cannot know the operating channel that other radio base stations are trying to use, the likelihood of conflict between the operating channels selected by each radio base station increases. To solve this, it is conceivable to install a central control unit to specify the channel for each radio base station, but this is systemically complex and the increase in cost cannot be ignored. Furthermore, for the W53 and W56 bands, which belong to 5GHz, radio wave regulations in various countries stipulate that a radio base station must perform a one-minute radar wave monitoring period called CAC (Channel Availability Check) before transmitting radio waves. During this time, transmitting radio waves is not permitted, and it becomes necessary to move to another channel where no radar waves are present.

[0005] The present invention has been made in view of the above circumstances, and its main objective is to provide a radio base station that selects an operating channel to avoid duplication of operating channels used for wireless communication when the startup timings of multiple radio base stations overlap in a communication system composed of multiple radio base stations. [Means for solving the problem]

[0006] A wireless base station according to one aspect of the present invention is a wireless base station in a communication system comprising a plurality of wireless base stations and a wireless terminal, comprising: a communication unit that searches for other wireless base stations using a search frame and transmits a channel response frame that notifies the operating channel to the search frame from the other wireless base station; a determination unit that determines whether or not other wireless base stations exist; and a processing unit that determines the operating channel that the unit will use to communicate with the wireless terminal, wherein the processing unit provisionally determines the operating channel, the determination unit determines whether or not other front-line base stations exist, (a) if the determination unit determines that no other wireless base stations exist, the processing unit selects the provisionally determined operating channel as the operating channel to be used by the unit, and thereafter, when the communication unit receives a search frame from another wireless base station, transmits the operating channel information currently used by the unit to the other wireless base station, and (b) if the determination unit determines that other wireless base stations exist, the communication unit receives the operating channel information currently used by the other wireless base station, and the processing unit re-selects an operating channel that does not match the said operating channel as the operating channel to be used by the unit.

[0007] According to this, a wireless base station in a communication system selects an operating channel to avoid overlap with channels used by existing wireless base stations. Therefore, each of the multiple wireless base stations in a communication system can autonomously select a different operating channel, thereby suppressing the deterioration of the wireless environment due to channel overlap.

[0008] Furthermore, the wireless base station may also include a timing unit that measures the delay time for its own startup, and the delay time may be determined randomly by a random number.

[0009] According to this, multiple radio base stations can be started up at different times, determine their own channels according to the startup order, and avoid overlapping operating channels with other radio base stations.

[0010] Furthermore, the communication unit may include a wireless communication unit including a first wireless module and a wired communication unit. The first wireless module may be used for first communication, which involves wireless communication with a wireless terminal connected to the unit, and the wired communication unit may be used for second communication, which involves sending and receiving search frames and operational channel information with other wireless base stations.

[0011] According to this, a wireless base station can independently perform wireless data frame communication with its subordinate wireless terminals and transmit and receive operational channel information with other wireless base stations.

[0012] Alternatively, the communication unit may include a wireless communication unit comprising a first wireless module and a second wireless module, the first wireless module being used for first communication to communicate wirelessly with a wireless terminal connected to the unit, and the second wireless module being used for second communication to send and receive search frames and operating channel information used by other wireless base stations with other wireless base stations.

[0013] This configuration also allows a wireless base station to independently perform wireless data frame communication with its subordinate wireless terminals and the transmission and reception of operational channel information with other wireless base stations.

[0014] Furthermore, a channel selection method according to one aspect of the present invention is a method for selecting an operating channel used for communication with a wireless terminal in a communication system comprising a plurality of wireless base stations and a wireless terminal, and includes the steps of: searching for other wireless base stations using a search frame; provisionally determining an operating channel; determining whether or not other wireless base stations exist; (a) if the determination step determines that no other wireless base stations exist, determining the provisionally determined operating channel as the operating channel to be used by the device; if a search frame is subsequently received from another wireless base station, transmitting the operating channel information currently used by the device to the other wireless base station; and (b) if the determination step determines that other wireless base stations exist, receiving the operating channel information currently used by the other wireless base station; and resetting an operating channel that does not match the operating channel included in the received operating channel information as the operating channel to be used by the device.

[0015] According to this, it will have the same effect as the wireless base station mentioned above. [Effects of the Invention]

[0016] According to the present invention, in a communication system with multiple wireless base stations, the operating channels used by each of the multiple wireless base stations for wireless communication can be autonomously selected to be the optimal operating channel without conflict. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 is a schematic diagram showing an overview of a communication system 100 according to an embodiment of the present invention. [Figure 2] Figure 2 is a schematic diagram showing an overview of a communication system 100a according to another embodiment of the present invention. [Figure 3] Figure 3 is a block diagram showing the functional configuration of a wireless base station according to an embodiment of the present invention. [Figure 4] Figure 4 is a flowchart showing the operation of a wireless base station according to an embodiment of the present invention. [Figure 5]FIG. 5 is a sequence diagram showing the processing until a radio base station in a radio communication system according to an embodiment of the present invention determines an operating channel via a backhaul.

Embodiments of the Invention

[0018] Hereinafter, embodiments will be specifically described with reference to the drawings. All of the embodiments described below show preferred specific examples of the present invention. The numerical values, shapes, components, arrangement positions and connection forms of the components, steps, order of steps, etc. shown in the following embodiments are merely examples and are not intended to limit the present invention. In addition, among the components in the following embodiments, components not described in the independent claims indicating the most general concept of the present invention are described as optional components constituting a more preferred form. Note that the same components are denoted by the same reference numerals, and the description may be omitted in some cases. [Embodiment]

[0019] In the present embodiment, an example in which information on an operating channel is shared among a plurality of radio base stations in a communication system 100 using a radio network or a wired network as a backhaul will be described. Hereinafter, the operating channel means a channel used by each radio base station for communication with subordinate radio terminals.

[0020] FIG. 1 is a schematic diagram showing an overview of a communication system 100 according to an embodiment of the present invention. As shown in FIG. 1, the communication system 100 includes an L2 switch 101, a wired link 102, a plurality of radio base stations (hereinafter also referred to as APs) 103a, 103b, 103c, a radio link 104, and a radio terminal (hereinafter also referred to as a STA) 105. The communication system 100 is a radio communication system constructed in, for example, an office or the like.

[0021] In the present embodiment, the communication system 100 includes three radio base stations 103a, 103b, and 103c. However, the present invention is not limited to this, and the number of radio base stations included in the communication system 100 may be two or four or more. Hereinafter, the plurality of radio base stations in FIG. 1 are also collectively referred to as radio base station 103. In the present embodiment, one radio terminal 105 is provided. However, the present invention is not limited to this, and one or more radio terminals 105 may be connected to each of the radio base stations 103.

[0022] The L2 switch 101 is connected to the radio base station 103 via the wired link 102. The L2 switch complies with a wired network standard such as IEEE802.3 and is connected to, for example, a network device, a corporate LAN, or the Internet.

[0023] The wired link 102 is a wired network that complies with the IEEE802.3 standard or the like. The wired link 102 connects each of the plurality of radio base stations 103 of the communication system 100 to the L2 switch 101 to form a mutual communication path. <{

[0024] The radio base station 103 complies with a standard such as IEEE802.11ac and performs wireless communication by forming a wireless network with the radio terminal 105 connected under its control. The radio base station 103 also has a function of transferring a data frame received via the wired link 102 to another wireless network or transferring a data frame received from the radio terminal to the wired network to which the wired link 102 is connected.

[0025] The wireless link 104 is a communication path for performing wireless communication between the radio base station 103 and the radio terminal 105. The radio base station 103 and the radio terminal 105 perform wireless communication that complies with a standard such as IEEE802.11ac via the wireless link 104 (corresponding to the first communication). In the first communication, for example, a frequency band in the 5 GHz band (corresponding to the first frequency band) is used to perform wireless communication between the radio base station 103 and the radio terminal 1%.

[0026] The wireless terminal 105 connects to the wireless base station 103 and performs wireless communication compliant with standards such as IEEE 802.11ac. The wireless terminal 105 can be a personal computer or a smartphone.

[0027] Figure 2 is a schematic diagram showing an overview of a communication system 100a with a different configuration of the present invention. It differs from the communication system 100 shown in Figure 1 in that communication between wireless base stations 103 is performed via a wireless link 201 instead of a wired link 102.

[0028] Wireless link 201 is a communication path used for wireless communication between multiple wireless base stations 103, and may use a different frequency band (corresponding to the second frequency band) than wireless link 104. Multiple wireless base stations 103 communicate via wireless link 201 using WDS (Wireless Distribution System) communication, and perform wireless communication compliant with standards such as IEEE 802.11ac (corresponding to the second communication). The second communication uses a frequency band such as 2.4 GHz to communicate wirelessly between multiple wireless base stations 103. By configuring wireless link 201 to use a different frequency band than that used by wireless link 104, radio interference is avoided when wireless link 201 and wireless link 104 communicate simultaneously.

[0029] Figure 3 is a block diagram showing the functional configuration of a wireless base station 103 according to an embodiment of the present invention. The wireless base station 103 is a type of computer, and in cooperation with each piece of hardware, the CPU reads programs stored in the auxiliary memory into the main memory and executes them, thereby functioning as a communication unit 302, a determination unit 304, a processing unit 305, a storage unit 306, and a timing unit 307. The communication unit 302 also includes a wireless communication unit 301 and a wired communication unit 303.

[0030] The wireless communication unit 301 includes a first wireless module 301a that performs wireless communication with the wireless terminal 105 using the first frequency band. Furthermore, the wireless base stations in the communication system 100a include a second wireless module 301b that performs wireless communication between base stations using a different frequency band (second frequency band) than the first wireless module 301a. The second wireless module 301b transmits and receives search frames with other wireless base stations 103, and as a response frame, transmits and receives channel response frames containing operating channel information with other wireless base stations. The wireless communication unit 301 also monitors a tentatively determined operating channel for a certain period of time in order to detect radar waves as defined by the Radio Law, etc. The wireless communication unit 301 is implemented using a wireless module, an antenna (not shown), and a driver program for the wireless module, and performs wireless communication with other wireless base stations 103 and wireless terminals 105 in accordance with standards such as IEEE802.11ac.

[0031] The wireless base station in the communication system 100 is equipped with a wired communication unit 103. The wired communication unit 303 transmits and receives search frames with other wireless base stations 103, and also transmits and receives channel response frames containing operational channel information with other wireless base stations as response frames. The wired communication unit 303 is implemented by a wired interface (not shown), and performs wired communication between the wireless base station 103 and wired network equipment such as an L2 switch 101, in accordance with standards such as IEEE 802.3.

[0032] The determination unit 304 determines whether or not other wireless base stations exist. The determination unit 304 may be implemented as a computer using a CPU (Central Processing Unit) or RAM (Random Access Memory), or it may be implemented as a program that has the same determination effect.

[0033] The processing unit 305 performs communication control processing based on information from the determination unit 304, the storage unit 306, and the timing unit 307. Specifically, in order to determine the operating channel, set the operating channel, and find out whether or not other wireless base stations exist, it causes the wired communication unit 303 or the second wireless module 301b to send a search frame that is determined independently, and notifies the determination unit 304 of the response result. The specific details of the processing will be described later. The processing unit 305 may be implemented using a CPU, RAM, etc.

[0034] The memory unit 306 stores information such as the provisionally determined operating channel, operating channels currently in use by other wireless base stations, and connection information. The memory unit 306 may be implemented using a volatile storage device such as RAM, or it may be implemented using a non-volatile storage device such as eMMC (Embedded Multimedia Card), SSD (Solid State Drive), or HDD (Hard Disk Drive).

[0035] The timing unit 307 measures the delay time required to delay the startup of the wireless base station 103 and notifies the processing unit 305. Specifically, the timing unit 307 counts down the delay time it has determined, and when the predetermined delay time has elapsed, it notifies the processing unit 305. The timing unit 307 randomly determines the delay time using random numbers or the like. The timing unit 307 may be implemented by hardware such as an RTC (Real Time Clock), or by software with similar functionality. [Description of the flow chart related to the embodiment]

[0036] Figure 4 is a flowchart showing the operation of the wireless base station 103 according to an embodiment of the present invention. Step S401 is a step in which the timing of when the wireless base station 103 starts operating is delayed by an arbitrary amount of time. By randomly delaying the timing of when the wireless base station 103 starts operating, it is avoided that all of the multiple wireless base stations 103 in the communication system will complete their startup process at the same time. In this step, the timing unit 307 notifies the processing unit 305 that a randomly determined delay time has elapsed, and based on this notification, the processing unit 305 starts up its own unit. At this time, the processing unit 305 also tentatively determines the operating channel that it intends to use.

[0037] Step S402 is a step in which the radio base station 103 searches the surrounding area using the provisionally determined operating channel. This search step is performed to confirm the absence of specific radio waves (radar waves) as defined by the radio wave laws of each country. The search period (monitoring period) is specifically, for example, 1 minute (60 seconds). This search is performed by the radio communication unit 301, and when the search period ends, the radio communication unit 301 notifies the processing unit 305 of the result. If radar waves are detected during the search, the processing unit 305 changes the provisionally determined operating channel and repeats step S402.

[0038] Step S403 is a step in which the wireless base station 103 searches for other wireless base stations 103 that may exist within the communication system. For example, in Figure 1, this is the step in which wireless base station 103a searches for wireless base stations 103b and 103c. This step is realized by communication between multiple wireless base stations 103 present in the communication system via the wired link 102 or wireless link 201, respectively, between the wired communication unit 303 or the second wireless module 301b. Specifically, the processing unit 305 controls the transmission of a search frame, which is determined independently by the unit itself, from the wired communication unit 303 or the second wireless module 301b of the other wireless base station 103 to the wired communication unit 303 or the second wireless module 301b of the other wireless base station 103.

[0039] Step S404 is a step in which the radio base station 103 determines whether or not it has detected the presence of another radio base station 103 as a result of the search in step S403. The presence of another radio base station 103 can be confirmed by receiving a channel response frame from another base station that is already running in response to the search frame, in which case the other base station will notify the operating channel. If the determination unit 304 determines that it has detected another radio base station 103 (Yes in step S404), it notifies the storage unit 306 of this fact and proceeds to step S406. If the determination unit 304 determines that it has not detected another radio base station 103 (No in step S404), it notifies the processing unit 305 of this fact and proceeds to step S405.

[0040] Step S405 is the step in which the wireless base station 103 sets the operating channel to be used when it performs wireless communication with the wireless terminal 105, etc., using the wireless link 104. Specifically, once the processing unit 305 determines the operating channel, it notifies the wireless communication unit 301 of the determined operating channel. From here on, the first wireless module uses this notified channel as the operating channel to perform wireless communication with the wireless terminal, such as data frames.

[0041] Step S406 is the step of storing the channels already in use by other radio base stations 103 that were detected as a result of the search in step S403. When radio base station 103 receives a channel response frame that includes at least operating channel information transmitted by another radio base station 103 in response to the search frame transmitted by itself in step S403, it stores the channel information used by the other radio base station 103 included in the received channel response frame in its own storage unit 306.

[0042] Step S407 is a step in which, if the channel used by another radio base station stored in step S406 overlaps with the channel used by the radio base station 103, the radio base station 103 switches to the next channel after the channel tentatively determined when executing step S401. This switching refers to the operation in which, for example, as described later in Figure 5, if the channel tentatively determined by radio base station 103b is 100ch, and it is found from the channel response frame received from radio base station 103a that 100ch is an overlapping operating channel, radio base station 103b switches to the next channel suitable for communication (e.g., 116ch). After completing this step, step S403 may be executed again and repeated until the operating channel tentatively determined by the unit no longer matches the operating channel used by the other radio base station 103. In other words, the unit re-selects an operating channel that does not match the operating channel of the other radio base station as the operating channel to be used by the unit. As a result, the channels used by each radio base station 103 in the communication radio link 104 with their respective radio terminals 105, etc., will be different from each other, and the deterioration of the radio environment due to radio interference associated with the same channel (i.e., the same frequency) can be suppressed. [Sequence description]

[0043] Next, the sequence of behavior of communication system 100 or 100a according to this embodiment will be explained using the sequence diagram in Figure 5. In the explanation of Figure 5, the explanation will be based on the case in communication system 100a where, after a random time interval, each of the wireless base stations 103a, 103b, and 103c are started up, and the subsequent sequence is performed in that order.

[0044] First, within the communication system 100 (or 100a), power is turned on to each radio base station 103 (radio base stations 103a, b, and c). After a certain period of time has elapsed, the processing unit 305 starts up its own unit based on a notification from the timing unit 307 (steps S401a, b, and c).

[0045] Next, the radio base station 103a performs a channel search to confirm that no radar waves are detected for a certain period of time on the operating channel that it has tentatively decided to use, and confirms the tentative operating channel that it will use (step S402a).

[0046] Next, the wireless base station 103a performs an AP search to find out if there are any other APs besides its own (step S403a). For example, the wireless base station 103a transmits a search frame using the wired communication unit 303 or the second wireless module 301b (step S501a).

[0047] Meanwhile, base station 103b also starts up with a delay, but since it has not yet finished starting up when the search frame in step S501a is transmitted, it cannot respond to the search frame in step S501a (the same applies to base station 103c). After that, base station 103b completes its startup and performs channel searching in the same way as base station 103a, as described above (step S402b).

[0048] Returning to the sequence of the wireless base station 103a, the wireless base station 103a confirms that there is no response from any APs in the communication system and confirms the setting of the operating channel that was provisionally determined when step S402a was performed (100ch in the example of step S407 in Figure 4) (step S502a). Here, the operating channel is set to 100ch. At this stage, the wireless base station 103a has completed the series of flows after startup and is in a state where it communicates with its subordinate wireless terminals on that channel while waiting to receive discovery frames from other APs.

[0049] Next, once the radio base station 103b completes the channel search and tentatively determines the operating channel, it performs AP search (step S403b). Here, the tentatively determined channel is assumed to be 100ch. Similar to radio base station 103a, radio base station 103b transmits a search frame onto the radio network using its own wired communication unit 303 or second radio module 301b to search for other radio base stations (step S501b).

[0050] Next, since the radio base station 103a has already started operation at this point, upon receiving the search frame transmitted by the radio base station 103b in step S501b, the radio base station 103a responds with an operating channel information (indicating that the operating channel currently in use is 100ch) via a channel response frame (step S503a). The operating channel information that the radio base station 103a responds with is provided using the wired communication unit 303 or the second radio module 301b, similar to the search frame (step S504a). Note that the radio base station 103c is still in the startup process and cannot respond to the search frame transmitted by the radio base station 103b.

[0051] Next, when the radio base station 103b receives the operating channel information of the radio base station 103a from the channel response frame transmitted from the radio base station 103a in the previous step S504a, it remembers that the tentatively selected 100ch is already in use by the radio base station 103a and changes the operating channel (100ch) that it had tentatively selected (in the example in Figure 4, it is 116ch) (step S502b).

[0052] Meanwhile, once the startup process for the wireless base station 103c is complete, in step S402b, a channel search is performed in the same manner as for wireless base stations 103a and 103b, a provisional operating channel is determined, and then AP discovery is performed (step S403c).

[0053] Next, when the wireless base station 103c transmits a search frame using the wired communication unit 303 or the second wireless module 301b (step S501c), wireless base stations 103a and 103b receive the search frame. Since wireless base stations 103a and 103b are already using channels 100 and 116 respectively, they each include their own operating channel information in the channel response frame (steps S503a1, S504a1, S503b, and S504b).

[0054] When wireless base station 103c receives information from wireless base stations 103a and 103b that channels 100 and 116 are in use, respectively, if these overlap with the operating channel that the unit had tentatively decided on, it changes it (to channel 136 in the example in Figure 4) and sets it as the unit's operating channel (step S502c).

[0055] As a result, multiple radio base stations 103 in the communication system 100a select operating channels in the order that the base stations have finished starting up, and radio base stations that start up later select operating channels in a way that avoids channel overlap. This allows each of the multiple radio base stations in the communication system to automatically select an operating channel while suppressing deterioration of the radio environment.

[0056] In this embodiment, the multiple wireless base stations 103 were described as mutually transmitting and receiving AP search, search frame transmission, and the channels currently in use of each unit via the wireless communication unit 301 or the wired communication unit 303. However, in the communication system 100, these processes may be appropriately divided and assigned to the wireless communication unit 301 and the wired communication unit 303, respectively. Furthermore, in this embodiment, there is no particular mention of avoiding radar waves in the channel search step immediately after operation regarding the provisionally determined channel and the finally determined operating channel. However, in the channel search step, the ranking of candidate operating channels may be determined and stored by referring to the surrounding wireless environment (for example, the load factor for each channel, the floor noise level, etc.), and the highest-ranking (preferred) channel may be set as the provisionally determined channel. If this overlaps with the operating channel of the AP that was started earlier, the next highest-ranking channel may be selected as the operating channel.

[0057] Furthermore, the present invention can be implemented not only as a device, but also as a method in which the processing means constituting the device are steps, as a program that causes a computer to execute those steps, as a storage medium such as a computer-readable CD-ROM on which the program is recorded, or as information, data, or signals that represent the program. These programs, information, data, and signals may be distributed via a communication network such as the Internet. [Industrial applicability]

[0058] The present invention can be applied to wireless base stations that improve user convenience. Specifically, it can be applied to wireless base stations in communication systems that want to automatically select the operating channel to be used for wireless communication without user instruction, while avoiding channel conflicts for wireless communication. [Explanation of Symbols]

[0059] 100 Communication Systems 101 L2 Switch 102 Wired Link 103 Wireless base stations 104 Wireless Link 105 Wireless terminals 200 Communication Systems 201 Wireless Link 301 Wireless Communication Section 301a First Wireless Module 301b Second Wireless Module 302 Communications Department 303 Wired Communications Department 304 Judgment section 305 Processing Unit 306 Storage section 307 Timing section

Claims

1. A radio base station in a communication system including a plurality of radio base stations and a radio terminal, a communication unit that searches for another wireless base station by using an exploration frame, and transmits a channel response frame in response to the exploration frame from the other wireless base station, the channel response frame notifying the wireless terminal of an operating channel that the wireless terminal uses to communicate with the wireless terminal; a determination unit that determines whether or not the other wireless base station exists based on whether or not the communication unit has received the channel response frame; a processing unit for determining an operating channel to be used by the wireless device for communication with the wireless terminal; Equipped with After the processing unit tentatively determines the operating channel, the determination unit determines whether or not the other radio base station exists; (a) when the determination unit determines that the other radio base station is not present, The processing unit selects the provisionally determined operating channel as an operating channel to be used by the own device, Thereafter, when the communication unit receives the search frame from the other wireless base station, the communication unit transmits the channel response frame to the other wireless base station; (b) when the determination unit determines that the other radio base station is present, the communication unit receives an operating channel being used by the other radio base station from the channel response frame; the processing unit reselects an operation channel that does not match the operation channel as an operation channel to be used by the own device; Radio base station.

2. A timer unit is further provided for timing a delay time for starting the own device, The delay time is determined randomly by a random number. The radio base station according to claim 1.

3. the communication unit includes a wireless communication unit including a first wireless module and a wired communication unit; The wireless communication unit includes: The wireless communication device is used for a first communication for wirelessly communicating data frames with the wireless terminal connected to the wireless communication device; The wired communication unit is A second communication is used for transmitting and receiving the search frame and the operating channel in use between the other radio base station and the second radio base station. The radio base station according to claim 1 or 2.

4. The communication unit includes a wireless communication unit including a first wireless module and a second wireless module, and the first wireless module includes: The wireless communication device is used for a first communication for wirelessly communicating data frames with the wireless terminal connected to the wireless communication device; The second wireless module is The search frame and the operating channel in use between the other radio base station are used for a second communication for transmitting and receiving the search frame and the operating channel in use between the other radio base station and the other radio base station. The radio base station according to claim 1 or 2.

5. 1. A method for selecting an operating channel to be used for communication with a wireless terminal in a communication system including a plurality of wireless base stations and a wireless terminal, comprising: searching for other wireless base stations using a search frame; determining the operating channel; determining whether or not the other wireless base station is present; (a) when it is determined that the other radio base station is not present in the determining step, determining the provisionally determined operation channel as an operation channel to be used by the own device; a step of transmitting information of an operating channel being used by the own device to the other wireless base station when the own device subsequently receives the search frame from the other wireless base station; (b) when it is determined in the determining step that the other radio base station is present, receiving information of operating channels in use by the other radio base stations; resetting the operating channel not matching the received operating channel in use as the operating channel to be used by the own device; Including, Channel selection method.

6. A program for causing a computer to execute the channel selection method according to claim 5.

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