JP4825855B2 - Wireless communication system - Google Patents

Description

The present invention relates to wireless communication systems such as wireless ordering system in the restaurant.

  In recent years, with the increase of product menus and seasonal products in restaurants such as family restaurants, a portable wireless terminal that allows the staff to easily and quickly input and wirelessly transmit product data ordered by customers The use of the used wireless ordering system is increasing.

  This portable wireless terminal is also called a handy terminal, and is composed of a main body part and a lid body part that is openably and closably connected to the main body part via a hinge, and the inside of the main body part can be operated by opening the lid body part. Surfaces are exposed, and data on products ordered by customers can be input by touching these operation surfaces with fingers. The input data is wirelessly transmitted to a wireless master station (also referred to as an access point) installed in the store.

  The wireless master station has a selection function for selecting a specific frequency (channel) used for wireless communication. The channel selection method by the selection function includes a method in which the surrounding wireless environment is investigated in advance (site survey) and the channel to be used is determined in advance, or the wireless master station itself always investigates the surrounding wireless environment. There is a method to select automatically.

  With reference to the conceptual diagram shown in FIG. 8, a description will be given of a method in which the wireless master station itself always checks the surrounding wireless environment and automatically selects a channel. Circles surrounding the radio master stations 30a, 30b, and 30c indicate the radio environment investigation range of each radio master station, and circles surrounding the interference source 50 indicate the area where the interference source 50 affects the radio environment. Yes. The radio master stations 30a, 30b, and 30c are set to channels 1ch, 2ch, and 3ch, respectively, and the interference source 50 emits radio waves of 3ch. Since the wireless environment investigation range of the wireless master station 30c overlaps the range in which the interference source 50 affects the wireless environment, the wireless master station 30c can detect the presence of the interference source 50 by the wireless environment investigation. . In addition, since the radio wave emitted from the interference source 50 is 3ch like the wireless master station 30c, the radio wave emitted from the interference source 50 interferes with the wireless communication of the wireless master station 30c. Therefore, the wireless master station 30c changes the channel used by itself to another channel in order to avoid radio wave interference by the interference source 50.

The handy terminal searches for a wireless master station capable of wireless communication by performing a predetermined negotiation process, and performs wireless communication according to a channel used by the wireless master station. That is, the handy terminal itself does not have the right to determine the channel to be used in the wireless communication system. As a communication method for searching for a wireless master station capable of wireless communication on the wireless terminal side as described above, for example, a communication method of a mobile wireless terminal described in Patent Document 1 is known.
JP-A-7-59146

  As described above, the method in which the channel used by the wireless master station is determined in advance by a prior site survey cannot cope with a wireless environment that changes after the site survey. For example, when an electrical appliance such as a microwave oven is newly installed, an electromagnetic wave generated by the appliance becomes an interference source, which may interfere with wireless communication between the wireless master station and the handy terminal.

  Such a problem is solved by adopting a method in which the wireless master station constantly checks the surrounding wireless environment, but the following problem is newly generated. FIG. 9 is a conceptual diagram of the wireless environment investigation by the wireless master station as in FIG. In this example, the radio environment investigation range of each radio master station and the range where the interference source 50 affects the radio environment do not overlap. Therefore, each wireless master station cannot detect the presence of the interference source 50. However, when the handy terminal is in the vicinity of the interference source 50, the handy terminal is affected by a radio wave emitted from the interference source 50, and there is a possibility that a problem occurs in wireless communication with the wireless master station side. In such a case, inconveniences such as inability to perform ordering operations using the handy terminal occur around the interference source 50, and resources belonging to the wireless communication system cannot be utilized to the maximum extent.

The present invention has been made in consideration of such circumstances, and its purpose is to detect an interference source that cannot be detected only by a wireless environment investigation by a wireless master station to realize an optimal wireless environment and provide it for wireless communication. it is to provide a wireless communication system that can be used to maximize without waste of resources.

The present invention provides a wireless master station having channel switching means for selectively switching a channel to be used for wireless communication from a plurality of channels having different frequencies, and the wireless master station negotiates with the wireless master station for wireless communication. in a wireless communication system having a non-linear device having a negotiation means for setting the channel to be used the channel to its own use, before Kina line terminal includes a detection means for detecting a failure of communication with the wireless base station , Comprising: a terminal side investigation means for investigating the radio wave condition of each channel; and a survey result notifying means for notifying the wireless master station of the investigation result by the terminal side investigation means, wherein the radio master station is configured to receive the radio wave condition of each channel. and the parent station side survey means for investigating, on the basis of the findings by the master station side checking means, are used for wireless communication with the wireless terminal A determination means for determining the presence or absence of an interference source for the channel; and when the determination means determines that there is no interference source and a failure is detected by the detection means, the investigation result notified by the investigation result notification means A channel to be used is selected based on the result of the investigation by the master station side investigation means when it is determined by the determination means that there is an interference source and no failure is detected by the detection means. the selected, it is determined that the interference source by the determining means is, and when a malfunction is detected by said detecting means, and findings of the investigation result notification means by the notified findings and the master station side survey means Channel selection means for selecting a channel to be used based on the channel switching means. It is characterized by switching the channel to be used for communication channels in which the channel selecting means has selected.

According to the present invention in which such a measure is taken, an interference source that cannot be detected only by a wireless environment survey by the wireless master station is detected to realize an optimal wireless environment, and resources used for wireless communication are maximized without waste. it is possible to provide a wireless communication system capable.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating a configuration of a wireless communication system. In the wireless communication system, a POS (Point Of Sales) terminal 2, a server 3, and a wireless master station 4 are connected to each other via a wired LAN (Local Area Network) 1. A handy terminal (HT) 5 capable of wireless communication with the wireless master station 4 via radio waves is provided.

  The POS terminal 2 processes the transaction of the store where the wireless communication system is installed by the operation of the store clerk. The server 3 executes various tasks related to the network such as storing and managing accounting data by the POS terminal 2. The wireless master station 4 is also called an access point, and is installed at a predetermined position in the store such as a ceiling. The handy terminal 5 is owned by a store clerk and accepts input of orders. The order received is transmitted to the wireless master station 4 by wireless communication and then processed by the server 3 to issue an order slip by a printer (not shown) and order information to a kitchen display (not shown). Is displayed.

FIG. 2 is a block diagram showing a main configuration of the wireless master station 4.
The wireless master station 4 is equipped with a main control CPU 10, and a memory 11, a communication unit 12, a wireless communication unit 13, and a power supply circuit 14 are connected to the CPU 10.

  The memory 11 stores a control program and the like. The communication unit 12 connects the LAN 1, transmits data supplied from the CPU 10 to the server 3 via the LAN 1, receives data transmitted from the server 3, and transmits the data to the CPU 10. The wireless communication unit 13 is provided with a built-in antenna 13a, transmits data supplied from the CPU 10 as a radio wave together with a specific ID code by the built-in antenna 13a, and receives data transmitted from an external device to the CPU 10 Supply. The power supply circuit 14 converts the power supplied from the commercial power supply 15 into operating voltages for the CPU 10, the memory 11, the communication unit 12, and the wireless communication unit 13, and supplies them.

FIG. 3 is a block diagram showing a main configuration of the handy terminal 5.
The handy terminal 5 includes a main body portion 5a and a lid body portion 5b connected to the main body portion 5a through a hinge so as to be freely opened and closed.
A main control CPU 20 is mounted on the main body 5a, and a touch panel 21, an LCD display module 22, a memory 23, a wireless communication unit 24, and a power supply circuit 25 are connected to the CPU 20.

  The touch panel 21 and the LCD display module 22 constitute a main operation key unit for input by touch operation, and display an image pattern such as a product menu or operation keys on the LCD display module 22 and transmit it on the touch panel 21. indicate.

  The memory 23 is for storing control programs and input data. The wireless communication unit 24 is provided with a built-in antenna 24a, receives data transmitted from an external device, supplies the data to the CPU 20, and uses the built-in antenna 24a as a radio wave together with a specific ID code. send. This ID code is used to allow the wireless master station 4 to identify which handy terminal 5 is the data transmitted.

  The operation surface on the inner side of the lid 5b is provided with a fixed menu type operation sheet in which names and icons of a plurality of product menus are arranged vertically and horizontally as auxiliary data input means. The membrane key 27 is provided on the back side of the. The membrane key 27 has a large number of contact points that are selectively operated in response to a finger pressed against the operation sheet, and the CPU 20 is connected to the CPU 20 by a flexible connection piece 27a extending toward the main body 5a using the signals of these contact points as input data. Supply. The connection piece 27a accommodates a wiring pattern for data transmission and also accommodates a wiring pattern for taking in an operating voltage supplied from a power supply circuit 25 described later.

  The power supply circuit 25 converts the voltage of the battery 26 into operating voltages for the touch panel 21, the LCD display module 22, the membrane key 27, the CPU 20, the memory 23, and the wireless communication unit 24, and converts them into the touch panel 21, the LCD display module. 22, membrane key 27, CPU 20, memory 23, and wireless communication unit 24. The battery 26 is connected to a connector 29 via a charging circuit 28, and is charged as necessary by an external power source (not shown) connected to the connector 29.

Next, the effect | action by the above structures is demonstrated.
The handy terminal 5 negotiates the wireless communication with the wireless master station 4 at a predetermined timing in a state where the power is turned on, and uses the channel used by the wireless master station 4 within the wireless communication range. Set to channel (negotiation means). In addition, the handy terminal 5 monitors whether there is a problem in wireless communication with the wireless master station 4 using the channel set by the negotiation (communication monitoring means).

FIG. 4 is a flowchart of defect monitoring processing executed by the CPU 20 of the handy terminal 5. This process is executed based on a program stored in the memory 23.
First, the CPU 20 determines whether or not a failure has occurred in the wireless communication with the wireless master station 4 in ST101. Specifically, for example, the presence or absence of a defect is determined in consideration of the communication status such as whether data transmission retries have occurred frequently or whether it takes longer than usual to complete data transmission. This process is repeated until it is determined that a failure has occurred (No in ST101). When it is determined that a failure has occurred (Yes in ST101), a wireless environment investigation process is executed as ST102, and the radio wave of each channel is determined. Investigate the state (terminal side investigation means). Details of the wireless environment investigation process will be described later with reference to FIG. After the wireless environment investigation process, as ST103, an environmental failure notification for notifying the occurrence of a failure and a result of the wireless environment investigation are transmitted to the wireless master station 4 by wireless communication (investigation result notifying means).

FIG. 5 is a flowchart of the wireless environment investigation processing executed by the CPU 20 of the handy terminal 5. This process is executed based on a program stored in the memory 23.
First, the CPU 20 measures a usage rate P, which is a rate per unit time in which a channel currently set for wireless communication with the wireless master station 4 is used in the surrounding area as ST201. Specifically, among radio waves transmitted by other wireless master stations 4 and handy terminals 5 received during a predetermined time t, noises emitted from peripheral devices such as electric appliances installed around, The time λ when the radio wave having the same frequency as that of the channel is received is measured, and the usage rate P of the channel is calculated by dividing the time λ by the predetermined time t (P = t / λ). The usage rate P calculated in this way becomes large when there is an interference source having the same frequency as that of the channel around and the radio wave is frequently radiated. Then, the channel investigated in ST202 and the measured usage rate P are linked and stored in the memory 23. Thereafter, in ST203, it is determined whether or not the usage rate P of all channels has been measured.

  When it is determined that there is a channel whose usage rate P has not been measured (No in ST203), the setting is changed to an unmeasured channel as ST204, and the processing of ST201 and ST202, that is, the measurement of the usage rate P of that channel and the memory are performed again. Store the measurement results.

  On the other hand, when it is determined that the usage rate P of all the channels has been measured in the process of ST203 (Yes in ST203), the wireless environment investigation process ends. The wireless environment investigation result stored in the memory 23 in this way is transmitted to the wireless master station 4 in the process of ST103. The wireless master station 4 stores the wireless environment investigation result received from the handy terminal 5 in the memory 11.

Next, channel setting processing executed in the wireless master station 4 will be described.
FIG. 6 is a flowchart of processing executed by the CPU 10 of the wireless master station 4 in channel setting processing. This process is executed based on a program stored in the memory 11.
First, the CPU 10 executes a wireless environment investigation process as ST301 (master station side investigation means). In this process, similarly to the process executed by the CPU 20 of the handy terminal 5 described with reference to FIG. 5, the usage rate P of each channel is measured, and the investigated channel and the measured usage rate P are linked to the memory 11. Remember.

  Next, as ST302, it is determined whether or not there is an interference source in the currently set channel. Specifically, the usage rate P for the currently set channel stored in the memory 11 in the process of ST301 is referred to, and it is determined whether or not the usage rate P exceeds a predetermined reference value P0. That is, when the reference value P0 is exceeded (P> P0), it is determined that there is an interference source, and when the reference value is not exceeded (P <P0), it is determined that there is no interference source. Such a reference value P0 may be set to a value that becomes a boundary at which the wireless master station 4 and the handy terminal 5 can perform wireless communication satisfactorily according to the use environment.

If it is determined in step ST302 that there is an interference source (YES in ST302), whether or not the environmental failure notification (ST103) is received from any one of the handy terminals 5 constituting the wireless communication system as ST303. Judging. When it is determined that the environmental failure notification is received from the handy terminal 5 (Yes in ST303), the wireless environment investigation result of the wireless master station 4 itself and the wireless environment investigation result by the handy terminal 5 that transmitted the environmental failure notification as ST304 Based on the above, a channel is selected for which wireless communication is good for both the wireless master station 4 and the handy terminal 5.
For example, the usage rate P, which is the result of each wireless environment survey by the wireless master station 4 and the handy terminal 5, is compared for each channel, and one with the higher usage rate P is extracted for each channel. Then, the usage rate P of each channel extracted in this way is compared, and the channel with the lowest usage rate P is selected.
After the process of ST304, as ST305, the channel used for wireless communication with the handy terminal 5 is switched to the channel selected in the process of ST304 (channel switching means). Then, after waiting for a predetermined time as ST306, the wireless environment investigation process is executed again (ST301). This predetermined time may be set short when the wireless communication system is used in a place where the wireless environment may frequently change, and long when the system is used in a place where the wireless environment does not change so much. do it.

On the other hand, when it is determined in step ST303 that an environmental failure notification has not been received from the handy terminal 5 (No in ST303), the wireless parent station 4 itself is determined based on the wireless environment investigation result of the wireless parent station 4 as ST307. For the station 4, a channel that provides good radio communication is preferentially selected.
For example, the usage rate P of each channel, which is the wireless environment investigation result by the wireless master station 4, is compared, and the channel with the lowest usage rate P is selected.
After the process of ST307, the channel used for wireless communication with the handy terminal 5 is switched to the channel selected in the process of ST307 (ST305), and after waiting for a predetermined time (ST306), the wireless environment investigation process is executed again. (ST301).

Here, when it is determined in the process of ST302 that there is no interference source in the current channel (No in ST302), as in ST308, any one of the handy terminals 5 constituting the wireless communication system as in the process of ST303 is performed. It is determined whether or not the environmental fault notification (ST103) has been received. When it is determined that an environmental failure notification is received from the handy terminal 5 (Yes in ST308), wireless communication is performed for the handy terminal 5 based on the wireless environment investigation result by the handy terminal 5 that transmitted the environmental failure notification in ST309. Preferentially select channels that will be good.
For example, the usage rate P of each channel, which is a wireless environment investigation result by the handy terminal 5, is compared, and the channel with the lowest usage rate P is selected.
After the process of ST309, the channel used for wireless communication with the handy terminal 5 is switched to the channel selected in the process of ST309 (ST305), and after waiting for a predetermined time (ST306), the wireless environment investigation process is executed again. (ST301).

  On the other hand, if it is determined in ST308 that an environmental failure notification has not been received from the handy terminal 5 (No in ST308), the channel is not changed and a predetermined time is waited (ST306), and then the wireless environment investigation process is performed again. Is executed (ST301).

  The process of selecting a channel to be used based on the result of the wireless environment survey transmitted from the handy terminal 5 and the result of the wireless environment survey of the wireless master station 4 in the processes of ST304, ST307 and ST309 is the channel selection. Configure the means.

  Next, a survey concept of a radio environment survey by the radio master station 4 and the handy terminal 5 will be described with a specific example. FIG. 7 is a conceptual diagram of a radio environment investigation in the radio communication system. The circles surrounding the radio master stations 4a, 4b, 4c and the handy terminal 5 indicate the radio environment investigation ranges of the radio master stations 4a, 4b, 4c and the handy terminal 5, respectively, and the circle surrounding the interference source 50 is the interference. The range in which the source 50 affects the wireless environment is shown. The radio master stations 4a, 4b, and 4c are set to channels 1ch, 2ch, and 3ch, respectively, and the interference source 50 emits radio waves of 3ch. The range in which the interference source 50 affects the wireless environment does not overlap with any of the wireless environment investigation ranges of the wireless master stations 4a, 4b, and 4c. Therefore, depending on the wireless environment investigation (ST301) on the wireless master station side, the interference source 50 Existence cannot be detected. However, since the range in which the interference source 50 affects the wireless environment belongs to the wireless environment investigation range of the handy terminal 5, the frequency of the radio wave emitted by the interference source 50 in the wireless environment investigation (ST102) of the handy terminal 5 is determined. The usage rate P of a certain 3ch will be increased. Then, the result of the wireless environment investigation by the handy terminal 5 is transmitted to the wireless master station capable of wireless communication with the handy terminal 5 (ST103). In the wireless master station that has received the result of the wireless environment investigation, a channel to be used is selected in consideration of the result of the wireless environment investigation (ST304, 309).

  As described above, in the wireless communication system, the wireless environment is investigated not only in the wireless master station 4 but also in the handy terminal 5, so that the interference source is in a position where it cannot be detected from the wireless master station 4. However, it can be detected by the handy terminal 5. Therefore, compared with the conventional wireless communication system in which the wireless environment investigation is performed only by the wireless master station 4, the communication environment between the wireless master station 4 and the handy terminal 5 is reduced, and an optimal wireless environment can be realized.

  In addition, since there is no inconvenience such as inability to perform ordering operations with the handy terminal around the interference source, resources such as the wireless master station 4 and the handy terminal 5 belonging to the wireless communication system can be utilized to the maximum.

  In addition, this invention is not limited to the said embodiment as it is, In an implementation stage, in the range which does not deviate from the summary, each component can be deform | transformed and embodied suitably.

  For example, the transmission of the wireless environment investigation result from the handy terminal 5 to the wireless master station 4 executed in the process of ST103 is not executed in the trouble monitoring process, but is normally performed when negotiating with the wireless master station 4 You may make it transmit in communication.

  Further, in the wireless environment survey performed at the wireless master station 4 and the handy terminal 5, the radio wave usage rate P by the other wireless master station 4, the handy terminal 5, and peripheral devices is measured, but the present invention is not limited to this. Other parameters in place of the usage rate P may be determined. For example, the radio wave reception intensity (RSSI: Receive Signal Strength Indicator) of radio waves received from the surroundings is measured for each channel. In the channel setting process, a channel to be set may be selected based on the radio wave reception intensity of each channel measured by the wireless master station 4 and the handy terminal 5. In addition, the number of wireless master stations 4 and handy terminals 5 that use each channel may be investigated and used to select a channel to be set.

  Further, the channel setting process executed by the CPU 10 of the wireless master station 4 described with reference to FIG. 6 may be executed with the reception of the environmental failure notification from the handy terminal 5 as a trigger.

In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from the overall components shown in the embodiment.
Each invention described in the scope of claims of the present application is appended below.
[1] A wireless master station having channel switching means for selectively switching a channel to be used for wireless communication from a plurality of channels having different frequencies, and used by the wireless master station by negotiating wireless communication with the wireless master station In a wireless communication system having a portable wireless terminal provided with a negotiation means for setting a channel to be used by itself, the portable wireless terminal includes a terminal side investigation means for examining a radio wave state of each channel, Investigation result notifying means for notifying the wireless master station of the investigation result by the terminal side investigation means, the wireless master station comprising: a parent station side investigation means for examining a radio wave state of each channel; and the portable wireless terminal. The investigation result by the terminal side investigation means and the investigation result by the parent station side investigation means received by the investigation result notification means; Channel selection means for selecting a channel to be used based on the channel selection means, and the radio master station switches the channel used for radio communication to the channel selected by the channel selection means by the channel switching means. system.
[2] The portable wireless terminal further includes communication monitoring means for monitoring a failure in wireless communication with the wireless master station, and when the communication monitoring means detects a failure in wireless communication with the wireless master station. The radio communication system according to [1], wherein the radio wave condition of each channel is investigated by the terminal side investigation means, and the investigation result is notified to the wireless master station by the investigation result notification means.
[3] The terminal side investigation means and the master station side investigation means are means for measuring a usage rate for each channel as a radio wave state of each channel, and the channel selection means is a result of investigation by the terminal side investigation means. The channel to be used is selected based on the usage rate of each channel and the usage rate of each channel that is the result of the survey by the master station side surveying means, as described in [1] or [2] above Wireless communication system.
[4] Negotiate wireless communication with a wireless master station having channel switching means for selectively switching a channel to be used for wireless communication from a plurality of channels having different frequencies, and the channel used by the wireless master station is determined by itself In a portable wireless terminal equipped with a negotiation means for setting a channel to be used, a terminal-side investigation means for examining the radio wave state of each channel, and an investigation result notification for notifying the wireless master station of the investigation result by this terminal-side investigation means A portable wireless terminal.

The schematic diagram which shows the structure of the radio | wireless communications system in one Embodiment of this invention. The block diagram which shows the principal part structure of the radio | wireless master station in the embodiment. The block diagram which shows the principal part structure of the handy terminal in the embodiment. The flowchart of the malfunction monitoring process which CPU of a handy terminal performs in the same embodiment. The flowchart of the radio | wireless environment investigation process which CPU of a handy terminal performs in the embodiment. 4 is a flowchart of processing executed by the CPU of the wireless master station in channel setting processing in the embodiment. The conceptual diagram for demonstrating the radio | wireless environment investigation in the embodiment. The conceptual diagram for demonstrating the radio | wireless environment investigation by the conventional radio | wireless master station. The conceptual diagram for demonstrating the radio | wireless environment investigation by the conventional radio | wireless master station.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... LAN, 2 ... POS terminal, 3 ... Server, 4a, 4b, 4c ... Wireless master station, 5 ... Handy terminal, 50 ... Interference source

Claims (3)

A wireless master station having channel switching means for selectively switching a channel to be used for wireless communication from a plurality of channels having different frequencies, and a channel to be used by the wireless master station by performing a negotiation on the wireless communication with the wireless master station in a wireless communication system having a non-linear terminal itself with a negotiation means for setting the channel to be used, before quinic line terminal,
Detecting means for detecting a failure in communication with the wireless master station;
A terminal side survey means to investigate the radio wave condition of each channel;
Investigation result notification means for notifying the wireless master station of the investigation result by the terminal side investigation means,
The wireless master station is
The main station side investigation means to investigate the radio wave condition of each channel,
Based on the investigation result by the master station side investigation means, determination means for determining the presence or absence of an interference source for the channel used for wireless communication with the wireless terminal,
When it is determined by the determination means that there is no interference source, and a defect is detected by the detection means, a channel to be used is selected based on the investigation result notified by the investigation result notification means, and the determination means When it is determined that there is an interference source and no failure is detected by the detection means, a channel to be used is selected based on the investigation result of the master station side investigation means, and the determination means determines that there is an interference source is, and when a malfunction is detected by said detecting means, and channel selecting means for selecting a channel to be used based on the findings of the notified findings and the master station side checking means by said survey result notification means With
The wireless master station switches the channel used for wireless communication by the channel switching means to the channel selected by the channel selecting means. Before Kina line terminal, when a trouble by prior Symbol detection means of the wireless communication with the wireless base station is detect, investigate the radio wave condition for each channel by the terminal side checking means, the survey results of this study The wireless communication system according to claim 1, wherein a result notification means notifies the wireless master station. The terminal side investigation means and the master station side investigation means are means for measuring a usage rate for each channel as a radio wave state of each channel, and the investigation result notification means is a result of investigation by the terminal side investigation means. Notifying the wireless master station of the usage rate of each channel, and the channel selection means, if it is determined by the determination means that there is no interference source, and if a failure is detected by the detection means, the investigation result notification means If the channel to be used is selected based on the usage rate of each channel notified by the above, the determination unit determines that there is an interference source, and the detection unit has not detected a failure, the master station side investigation unit The channel to be used is selected based on the usage rate of each channel, which is the result of the survey, and it is determined by the determination means that there is an interference source, If a problem is detected by said detecting means, the channel to use based on said survey result notifying means utilization of each channel which is notified by the usage rate of each channel is a survey of the master station side survey means The wireless communication system according to claim 1, wherein the wireless communication system is selected.

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