JP2009284291A - Radio wave interference avoiding method of radio communication device, and radio communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication device that performs radio communication while interference caused by a microwave radiated by a magnetron is avoided. <P>SOLUTION: The radio communication device 1 detects an interference frequency band which periodically varies as the microwave varies in frequency as an incommunicable channel of a low-speed radio communication means 20 by ZigBee, and stores and holds it in a channel variation table in association with an elapsed time from the point of time when a microwave oven 12 starts operation (steps ST1 to ST5). When the channel variation table is stored and held, a communication channel of a frequency band avoiding an incommunicable channel associated with the elapsed time is set as a communication channel of the communication device 1 each time a measured time from the point of time when the microwave oven 12 starts operation (steps ST11 to ST14) reaches the elapsed time. Communication channels of three radio communication means 18 to 20 are set based on periodic variation in interference frequency band which is actually detected, so that interference caused by a microwave is always avoidable. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radio wave interference avoiding method for a radio communication device capable of communicating while avoiding radio wave interference caused by microwaves radiated by operation of a magnetron built-in device such as a microwave oven, and a radio communication device.

  In an order entry system built in a restaurant or the like, when a food order is input from an order entry terminal arranged in a guest room, the order information is stored and held in a server installed in an office. In addition, a cooking instruction slip on which the name of the ordered dish is printed is issued from a printer installed in the kitchen. These order entry terminals, servers, and printers are configured to transmit information by wireless communication. As communication standards for wireless communication, IEEE802.11b / g, Bluetooth (registered trademark), ZigBee (registered trademark), etc. Those using the 2.4 MHz band ISM band are widespread.

  A microwave oven is installed in the restaurant kitchen to heat the food. A microwave oven heats food with microwaves generated by a magnetron, and when the magnetron operates, microwaves in the 2.4 MHz band leak from the microwave oven. For this reason, when food is heated, radio wave interference occurs between the microwave leaking from the microwave oven and the wireless communication, and the communication channel used for the wireless communication between the order entry terminal, the server and the printer is Communication may be lost.

A method for searching for a communication channel that is less affected by radio wave interference when a magnetron is operated is disclosed in Patent Document 1. A wireless communication apparatus that performs communication by switching a communication channel to another communication channel when radio wave interference occurs is disclosed in Patent Document 2. In addition, when communicating with two communication means that use the same frequency band, a wireless communication apparatus that assigns communication channels of each communication means so that frequency bands do not overlap so that interference does not occur between the two communication means Is described in Patent Document 3.
JP 2003-9229 A JP 2006-33256 A JP 2006-352820 A

  The frequency of a microwave generated by a magnetron such as a microwave oven fluctuates in a cycle having both long and short periodicities. For this reason, a communication channel that is incapable of communication due to microwave interference fluctuates periodically with the elapsed time from the start of operation of the magnetron. In addition, there are individual differences depending on the magnetron in the spectrum distribution of the microwave and the frequency fluctuation period. Therefore, there is a problem that it is difficult for the premises where the microwave oven is installed to perform wireless communication in a state where the influence of the radio wave interference due to the microwave is always avoided.

  In view of the above-described problems, an object of the present invention is to provide a radio interference avoidance method and radio communication apparatus for a radio communication apparatus capable of performing radio communication in a state in which the influence of radio wave interference caused by microwaves emitted from a magnetron is always avoided. It is to propose.

In order to solve the above-described problem, a radio wave interference avoiding method of the wireless communication device of the present invention is
After detecting the operation start time of the magnetron, the interference frequency band in which the radio wave is generated is detected until the operation stop time of the magnetron is detected, and the interference frequency band and the interference frequency band are determined from the operation start time. A frequency band specifying step for storing and holding the elapsed time until detection in a correlated form;
The time from when the operation start time of the magnetron is detected to when the operation stop time is detected is measured, and when the measurement time reaches the elapsed time, the interference frequency band associated with the elapsed time And a channel setting step for setting a communication channel that avoids the problem.

  According to the present invention, an interference frequency band that periodically changes with frequency fluctuations of the microwave generated by the magnetron is actually detected, and this interference frequency band is associated with an elapsed time from the operation start time of the magnetron. And remember it. In addition, after the interference frequency band and the elapsed time are stored and held in association with each other, the communication channel of the wireless communication device is set to the elapsed time every time the measurement time from the operation start time of the magnetron becomes the elapsed time. Is set to a communication channel that avoids the interference frequency band associated with. As a result, the wireless communication apparatus can communicate using a communication channel that is not affected by radio wave interference caused by microwaves. In addition, since the communication channel is set based on periodic changes in the actually detected interference frequency band, even if there are individual differences due to magnetron in the spectrum distribution of the microwave and the frequency fluctuation period, it is always Wireless communication can be performed while avoiding the influence of radio wave interference caused by waves.

  In the present invention, in order to detect an interference frequency band, in the frequency band specifying step, the communication impossible channel cannot be communicated by causing the first communication means that communicates in the specific frequency band to perform frequency hopping at a predetermined interval. It is desirable to detect and store the communication disabled channel as the interference frequency band. The specific frequency band includes a 2.4 MHz band for specific power saving.

  In the present invention, in order to communicate using a communication channel that avoids an interference frequency band, in the frequency band specifying step, a communicable channel capable of communicating simultaneously with the detection of the communicable channel is detected, and the communicable channel is detected. And storing and holding the communicable channel and the elapsed time in a correlated form, and in the channel setting step, when the measurement time reaches the elapsed time, the communicable channel associated with the elapsed time is stored. It is desirable to set as a communication channel for the first communication means.

  In the present invention, when the wireless communication apparatus includes two different communication means, in order to prevent interference between the communication means, in the channel setting step, the first communication means When setting communication channels of different second communication means, it is desirable to set so as not to overlap the frequency band of the communication channel of the first communication means. That is, each communication channel of two different communication means is set so as to avoid the interference frequency band, and is set so that the frequency bands do not overlap each other.

  In the present invention, in order to detect an interference frequency band, it is preferable that the first communication means is a weak radio system. There are ZigBee and the like as weak wireless systems, which are suitable for detecting an interference frequency band because they have a small transmission output and are susceptible to radio wave interference. Moreover, since ZigBee has a narrow frequency band for each communication channel of 2 MHz, the interference frequency band can be detected with high accuracy.

  In the present invention, in order to detect the operation start time and operation stop time of the magnetron of the magnetron built-in device, the sensor includes a sensor installation step of attaching an induction coil to the power cord of the magnetron built-in device, the frequency band specifying step and the channel setting In the step, it is desirable to detect the operation start time and the operation stop time based on an electrical change generated in the induction coil.

  In addition, in order to detect the operation start time and operation stop time of the magnetron of the magnetron built-in device, voltage fluctuation detection means for detecting a change in the power supply voltage of the power line supplying power to the magnetron built-in device is attached to the power line. In the frequency band specifying step and the channel setting step, including a sensor installation step, it is desirable to detect an operation start time and an operation stop time of the magnetron based on a change in the power supply voltage.

  In addition, in order to detect the operation start time and operation stop time of the magnetron of the magnetron built-in device by the first communication means, in the frequency band specifying step and the channel setting step, the first communication means has a frequency at the predetermined interval. It is desirable to perform hopping and detect the time when the communication disabled channel is first detected as the operation start time and the time when the communication disabled channel is not detected as the operation stop time.

Next, the wireless communication apparatus of the present invention is
Operation detecting means for detecting the operation start time and operation stop time of the magnetron;
The interference frequency band in which radio waves are generated is detected from the operation start time to the operation stop time, and the interference frequency band is associated with the elapsed time from the operation start time to the detection of the interference frequency band. Frequency band specifying means for storing and holding in a
When the interference frequency band and the elapsed time are stored and held in a correlated form, the time from the operation start time to the operation stop time is measured, and when the measurement time becomes the elapsed time, Channel setting means for setting a communication channel that avoids the interference frequency band associated with the elapsed time.

  According to the present invention, the frequency band specifying means actually detects an interference frequency band that periodically changes in accordance with the frequency fluctuation of the microwave generated by the magnetron, and the elapsed time from the operation start time of the interference frequency band and the magnetron. The time is stored in association with each other. In addition, when the interference frequency band and the elapsed time are stored and held in association with each other, the channel setting unit performs the measurement of the radio communication device every time the measurement time from the operation start time of the magnetron becomes the elapsed time. A communication channel that avoids the interference frequency band associated with the elapsed time is set as the communication channel. As a result, the wireless communication apparatus can communicate using a communication channel that is not affected by radio wave interference caused by microwaves. In addition, since the communication channel is set based on the periodic change of the actually detected interference frequency band, even if there is an individual difference due to the magnetron in the spectrum distribution of the microwave and the period of frequency fluctuation, it is always the microwave. Wireless communication can be performed in a state where the influence of radio wave interference due to is avoided.

  In the present invention, in order to detect an interference frequency band, it has first communication means of a communication standard that communicates in a specific frequency band, and the frequency band specifying means has a frequency at a predetermined interval to the first communication means. It is desirable to detect a communication impossible channel that cannot be communicated by performing hopping, and store and hold the communication disabled channel as the interference frequency band.

  In the present invention, in order to communicate on a communication channel that avoids an interference frequency band, the frequency band specifying means detects a communicable channel that can be communicated simultaneously with the detection of the communicable channel, and The channel setting means stores the communicable channel associated with the elapsed time when the measurement time reaches the elapsed time. It is desirable to set as a communication channel for the first communication means.

  In the present invention, when the wireless communication means includes two communication means having different communication standards, in order to prevent interference between the communication means, the second different from the first communication means. It is desirable that communication means be provided and the channel setting means is set so as not to overlap a frequency band of the communication channel of the first communication means when setting the communication channel of the second communication means. That is, each communication channel of two different communication means is set so as to avoid the interference frequency band, and is set so that the frequency bands do not overlap each other.

  In the present invention, in order to detect an interference frequency band, it is preferable that the first communication means is a weak radio system. There are ZigBee and the like as weak wireless systems, which are suitable for detecting an interference frequency band because they have a small transmission output and are susceptible to radio wave interference. Moreover, since ZigBee has a narrow frequency band for each communication channel of 2 MHz, the interference frequency band can be detected with high accuracy.

  In the present invention, in order to detect the operation start time and the operation stop time of the magnetron of the magnetron built-in device, it has an induction coil attached to a power cord of a microwave oven, and the operation detection means is connected to the induction coil. It is desirable to detect the operation start time and the operation stop time based on the generated electrical change.

  In the present invention, in order to detect the operation start time and the operation stop time of the magnetron of the magnetron built-in device, the power line is connected to the power line to detect a change in the power supply voltage of the power line supplying power to the magnetron built-in device. It is preferable that a voltage fluctuation detection unit is attached, and the operation detection unit detects the operation start time and the operation stop time based on a change in the power supply voltage.

  In order to detect the operation start time and operation stop time of the magnetron of the magnetron built-in device by the first communication means, the operation detection means causes the first communication means to perform frequency hopping at the predetermined interval, Preferably, the time point when the communication disabled channel is detected is detected as the operation start time point, and the time point when the communication disabled channel is not detected is detected as the operation stop time point.

  According to the present invention, an interference frequency band that periodically changes with frequency fluctuations of the microwave generated by the magnetron is actually detected, and this interference frequency band is associated with an elapsed time from the operation start time of the magnetron. And remember it. In addition, after the interference frequency band and the elapsed time are stored and held in association with each other, the communication channel of the wireless communication device is set to the elapsed time every time the measurement time from the operation start time of the magnetron becomes the elapsed time. Is set to a communication channel that avoids the interference frequency band associated with. As a result, the wireless communication apparatus can communicate using a communication channel that is not affected by radio wave interference caused by microwaves. In addition, since the communication channel is set based on periodic changes in the actually detected interference frequency band, even if there are individual differences due to magnetron in the spectrum distribution of the microwave and the frequency fluctuation period, it is always Wireless communication can be performed while avoiding the influence of radio wave interference caused by waves.

  Embodiments of a communication apparatus to which the present invention is applied will be described below with reference to the drawings.

(Communication device)
FIG. 1 is an external perspective view of a communication apparatus according to the present embodiment. The communication device 1 of the present invention supplies DC power to a printer (equipment) 2 connected to the communication device 1 and provides functions of power line communication and wireless communication.

  The communication device 1 has a power cord 3 that is connected to a power line by being plugged into an outlet, a device body 4 that is a rectangular parallelepiped, and a connection cord 5 that connects the device body 4 and equipment. The connection cord 5 is branched into two in the middle, and a communication connector 6 for performing communication between the communication device 1 and the device is attached to the tip of one cord portion 5a. A power connector 7 for supplying power from the communication device 1 to the printer 2 is attached to the tip of the other cord portion 5b.

  FIG. 2 is a block diagram of the communication device 1. The communication device 1 includes a communication unit 11 for connecting the power supply unit 10 and the printer 2 connected to the communication device 1 to a communication network. In addition, a radio wave interference avoiding unit 13 is provided for avoiding communication failure due to microwaves radiated from the microwave oven 12 connected to the power line 8. Details of the radio wave interference avoiding unit 13 will be described later.

  The power supply unit 10 functions as an AC adapter, and converts AC power supplied from the power line 8 via the power cord 3 into predetermined DC power. Further, the converted DC power is supplied from the connection cord 5 to the printer 2 via the power connector 7.

  The communication unit 11 is configured around a control unit 15 including a CPU, a ROM, and a RAM. A communication unit 16 that communicates between the printer 2 and the communication device 1 is connected to the printer 2 side of the control unit 15. On the communication network side, there are three power line communication means 17 that communicates between an external device and the communication means 16 via the power line 8, and three different communication standards for wireless communication between the external device and the communication means 16. Wireless communication means 18 to 20 are connected. The control unit 15 includes channel setting means 21, communication state monitoring means 22, communication control means 23, and drive control means 24. Here, the external device is an information device such as the server 14 connected to the communication network, and includes other communication devices connected to the communication network and devices connected to other communication devices. Yes.

  The communication means 16 performs wired communication with the printer 2 via the connection cord 5 and the communication connector 6. In this example, the communication connector 6 is connected to the LAN port for communication. The communication means 16 may be connected to a general-purpose communication interface such as a parallel bus, USB (Universal Serial Bus), or serial port for communication.

  The power line communication means 17 is a PLC (Power Line Communication) modem that performs data communication by superimposing a predetermined high frequency on the power line 8. Communication standards for power line communication include a plurality of communication standards provided by PLC modem vendors. In this example, power line communication of a communication standard with a communication speed of 30 Mbps is used.

  The three wireless communication units 18 to 20 are a high-speed wireless communication unit 18 having a communication standard of IEEE 802.11g, a medium-speed wireless communication unit 19 having a communication standard of IEEE 802.11b, and a low-speed wireless communication unit 20 having a communication standard of ZigBee. . Both are wireless communication modems that perform communication using the 2.4 MHz band ISM band. The high-speed wireless communication means 18 and the medium-speed wireless communication means 19 can function as access points of the wireless communication network by operating the setting switch 25. The communication speed according to the IEEE 802.11g communication standard is 54 Mbps, the communication speed according to the IEEE 802.11b communication standard is 11 Mbps, and the communication speed according to the ZigBee communication standard is 250 kbps.

  The channel setting means 21 assigns so that the frequency bands of the communication channels used by the three wireless communication means 18 to 20 do not overlap each other. FIG. 3 (a) is a list of IEEE 802.11b / g and ZigBee communication channels in the 2.4 MHz band. FIG. 2B shows an example in which the channel setting means 21 is set so that the communication channels of the three wireless communication means 18 to 20 do not overlap.

  As shown in FIG. 3A, IEEE802.11b / g has 14 communication channels in the 2.4 MHz band, and ZigBee has 16 communication channels. Therefore, for example, the channel setting means 21 assigns channel 1 which is a communication channel in the 2412 MHz frequency band to the high-speed wireless communication means 18 that communicates by IEEE802.11g, and 2437 MHz to the medium-speed wireless communication means 19 that communicates by IEEE802.11b. Channel 6 which is a communication channel in the frequency band is assigned. Also, any one of channel 20 to channel 26 is assigned to ZigBee.

  Here, when each of the wireless communication units 18 to 20 has a function of dynamically changing a communication channel while detecting a communicable channel capable of communication, the channel setting unit 21 The communication channels changed by the wireless communication means 18 to 20 are acquired and assigned so that they do not overlap the same frequency band.

  When communication is performed by the power line communication unit 17 and any one of the three wireless communication units 18 to 20, the communication state monitoring unit 22 is connected to the wireless communication unit 18 of the power line communication units 17 and 3. When the low-speed wireless communication means 20 is not the slowest communication speed in the communication standard among ˜20, it is monitored whether or not the communication speed at which communication is performed falls below a preset allowable speed. . The allowable speed of the high-speed wireless communication means 18 that performs communication by IEEE802.11g is 6 Mbps, the allowable speed of the power line communication means 17 is 3 Mbps, and the allowable speed of the medium-speed wireless communication means that performs communication by IEEE802.11b is 1 Mbps. Each permissible speed is set to about 1/3 of the communication speed that can be practically used in the power line communication and the high-speed and medium-speed wireless communication means 18 and 19. In general, the communication speed is reduced before communication is disabled. Therefore, by switching the communication units 17 to 20 in this way, it is possible to avoid the communication environment from being changed and communication disabled.

  The communication control unit 23 causes the power line communication unit 17 and any one of the three wireless communication units 18 to 20 to perform communication. When the communication starts, the power line communication unit 17 and the three wireless communication units The communication quality according to 18 to 20 is evaluated, and communication is performed by one communication means having the highest communication quality. Communication quality can be evaluated based on error rate, SNR, communication speed, and the like. The error rate, SNR, and communication speed can be obtained by known methods. These evaluations can be performed using threshold values.

  Further, when it is detected that the communication speed of the communication means that is performing communication falls below the allowable speed, the communication control means 23 determines the communication standard from the power line communication means 17 and the three wireless communication means 18-20. The communication speed is switched to the communication means having the next highest communication speed after the communication means with which communication is performed, and communication is performed.

  FIG. 4 is an explanatory diagram schematically showing an operation in which the communication control unit 23 performs communication while switching between the power line communication and the three wireless communication units 18 to 20. As shown in FIG. 4, when the communication speed falls below the allowable speed during communication with the high-speed wireless communication means 18, the power line communication means 17 performs communication instead of the high-speed wireless communication means 18. When the communication speed of the power line communication means 17 falls below the allowable speed, the medium speed wireless communication means 19 is made to communicate instead of the power line communication means 17. When the communication speed of the medium-speed wireless communication means 19 falls below the allowable speed, the low-speed wireless communication means 20 is made to communicate instead of the medium-speed wireless communication means 19. That is, when the communication environment changes during the communication and the communication speed becomes less than the allowable speed, the communication means having the communication speed according to the communication standard is sequentially switched from the fast communication means to the slow communication means. When communication is performed by the low-speed wireless communication unit 20, the communication by the low-speed wireless communication unit 20 is maintained.

  When one of the power line communication unit 17 and the three wireless communication units 18 to 20 receives a control command for driving and controlling the printer 2 via the communication network, the drive control unit 24, based on the received control command, The printer 2 is started from the standby state or is made to wait from the driving state.

  When the power cord 3 of the communication device 1 is plugged into an outlet and the power connector 7 of the connection cord 5 is connected to the printer 2, the power supply unit 10 converts AC power into predetermined DC power and supplies it to the printer 2. If the communication connector 6 of the connection cord 5 is connected to the communication interface of the printer 2, the communication device 1 adds a power line communication function and a wireless communication function to the printer 2. That is, the printer 2 is connected to the power line communication network via the communication unit 16 and the power line communication unit 17 and can communicate with an external device. In addition, the printer 2 is connected to three wireless communication networks via the communication means 16 and three wireless communication means 18 to 20 using communication channels that do not overlap in frequency bands, or is connected to other communication devices in an ad hoc mode. It becomes possible to communicate with external devices.

  Therefore, even when the printer 2 does not have the power line communication and wireless communication functions, the power line communication and the wireless communication can be added to the printer 2, and status information such as an error state and a busy state of the printer 2 can be externally transmitted. The device can be notified. Even when the printer 2 connected to the communication device 1 fails, the failure state can be notified from the communication device 1 to the external printer 2 via the communication network and the communication network. Furthermore, since the communication apparatus 1 has the drive control means 24, the printer 2 can be started from a standby state from an external device via a communication network. Or it can be made to stand by from a drive state.

  The communication device 1 includes three wireless communication units 18 to 20 having different communication standards. Therefore, even when wireless communication by one wireless communication unit becomes impossible, communication can be performed using another wireless communication unit. Furthermore, since the communication standards of the wireless communication units 18 to 20 are different from each other, even when one wireless communication unit becomes unable to communicate, there is a possibility that communication can be performed by another wireless communication unit. In addition, since the power line communication means 17 is provided, the case where communication becomes impossible can be avoided or reduced.

(Radio interference avoidance unit)
Here, the radio wave interference avoiding unit 13 will be described. The radio wave interference avoiding unit 13 is connected to the power line 8 when the communication device 1 and the printer 2 connected to the communication device 1 constitute a part of an order entry system in a restaurant. This is to prevent the wireless communication of each of the wireless communication means 18 to 20 from being disabled due to the microwaves emitted from the magnetron.

  As shown in FIG. 2, the radio wave interference avoiding unit 13 includes a microwave operation detecting unit 26, a channel specifying unit (frequency band specifying unit) 27, and a channel setting unit 21. The channel specifying unit 27 is configured in the control unit 15. The channel setting means 21 operates in both the communication unit 11 and the radio wave interference avoiding unit 13.

  The microwave operation detecting means 26 detects the operation state of the microwave oven 12, that is, the operation state of the magnetron of the microwave oven 12. A voltage fluctuation detecting means 28 for detecting a change in the power supply voltage of the power line 8 and an operation detecting means 29 for detecting the operation start time and the operation stop time of the microwave oven 12 based on the change in the power supply voltage are provided. The operation detection unit 29 is configured in the control unit 15. When the voltage fluctuation detection unit 28 detects that the power supply voltage of the power line 8 has dropped instantaneously, the operation detection unit 29 detects this as the operation start time of the microwave oven 12. When the voltage fluctuation detecting unit 28 detects that the power supply voltage of the power line 8 has risen instantaneously, the operation detecting unit 29 detects this as the operation stop time of the microwave oven 12. Here, as shown in FIG. 5, the microwave operation detecting means 26 is connected to the communication device 1 by using the induction coil 30 attached to the power cord of the microwave oven 12 and the electrical change generated in the induction coil 30 as a predetermined signal. The transmission means 31 for transmission and the operation detection means for detecting the operation start time and the operation stop time of the microwave oven 12 by receiving a predetermined signal may be used.

  The channel specifying unit 27 detects an interference frequency band in which radio wave interference occurs while the microwave oven 12 is operating. In this example, a communication impossible channel that cannot be communicated is detected by causing the communication means of the communication standard that communicates in the 2.4 MHz band to perform frequency hopping, and this communication disabled channel is stored and held as an interference frequency band. In addition, the channel specifying unit 27 detects a communicable channel that can communicate without receiving radio wave interference at the same time as detecting a communication impossible channel.

  Here, the frequency of the 2.4 MHz band microwave generated by the magnetron of the microwave oven 12 fluctuates with a period having both long and short periodicities. As a result, the communication channel of each communication standard that becomes incapable of communication due to the interference of the microwave periodically varies with the elapsed time from the operation start time of the microwave oven. Therefore, the communication channel specifying unit 27 detects the communication disabled channel and the communication enabled channel at predetermined intervals from the operation start time to the operation stop time of the microwave oven 12, and detects the detected communication disabled channel and the detected communication enabled channel. It stores and holds as a channel fluctuation table in which the communication impossible channel and the elapsed time from the start of operation of the microwave oven 12 to the detection of the communication possible channel are associated with each other.

  A well-known technique for detecting these channels while performing frequency hopping is used to detect the communication disabled channel and the communication enabled channel. In this example, the low-speed wireless communication means 20 that communicates with ZigBee, which has a small transmission output and is susceptible to radio wave interference, is used as a sensor to detect a communication disabled channel and a communication enabled channel. In this example, the predetermined interval is set to 100 ms, and the communication impossible channel and the communication possible channel are detected every 100 ms after the operation start time of the microwave oven 12 is detected.

  Note that the channel variation table stored and held in the control unit 15 is accessible to other communication devices in order to share with other communication devices communicable with the communication device 1. Further, when another communication device accesses, the channel variation table can be stored and held in the control unit of the other communication device accessed.

  Next, when the channel variation table is stored and held in the control unit 15, the channel setting unit 21 allocates the communication channels of the wireless communication units 18 to 20 based on the channel variation table when the microwave oven 12 operates. . That is, when the microwave oven 12 operates, the channel setting means 21 refers to the communication disabled channel and the communication enabled channel in the channel fluctuation table at predetermined intervals from the operation start time. Then, the channel setting unit 21 sets any one of the communicable channels as a low-speed wireless while preventing the frequency bands of the communication channels of the wireless communication units 18 to 20 from overlapping as in the case of operating as a part of the communication unit 11. The communication channel of the communication unit 20 is allocated, and any one of a plurality of communication channels not including the frequency band of the communication disabled channel is allocated to the high-speed wireless communication unit 18 and the medium-speed wireless communication unit 19, respectively.

  FIG. 6 is a flowchart showing an operation of assigning communication channels so as not to interfere with microwaves. FIG. 6A shows an operation of storing and holding the communication enable channel and the communication disable channel as a channel variation table, and FIG. 6B shows an operation of setting the communication channel. FIG. 7A is an explanatory diagram schematically showing microwaves generated while the microwave oven 12 is operating. FIG. 7B is an explanatory diagram schematically showing an example of an operation in which the communication disable channel and the communication enable channel are detected by the low-speed wireless communication means 20 while the microwave oven 12 is operating. FIG. 7C is a channel fluctuation table in which the detected communication disabled channel and the communication enabled channel are associated with the elapsed time from the operation start time of the microwave oven 12. FIG. 8 is an explanatory diagram showing an example in which communication channels are assigned to avoid radio wave interference.

  As shown in FIG. 6 (a), when the microwave operation detecting means 26 detects the operation start time of the microwave oven 12 (step ST1), after 100 ms have passed (step ST2), the channel specifying means 27 determines the communication disabled channel and the communication. A possible channel is detected (step ST3). Further, the detected communication disabled channel and the communication enabled channel are stored and held in the channel fluctuation table in association with the elapsed time from the operation start time (step ST4). Thereafter, until the operation stop time of the microwave oven 12 is detected in step ST5, the communication impossible channel and the communication possible channel are detected and stored at intervals of 100 ms (steps ST2 to ST4).

  Here, when the microwave operation detecting means 26 detects the operation start time of the microwave oven 12, as shown in FIG. 7A, microwaves that change periodically are emitted from the microwave oven 12. Further, the channel specifying means 27 detects a communication disabled channel and a communication enabled channel that change due to this periodicity. In the example shown in FIG. 7B, the channel 13 and the channel 20 are detected as non-communication channels when 100 ms elapses from the operation start time of the microwave oven 12 (indicated by x in the figure), and the channel 14, the channel 15, Channel 18 is detected as a communicable channel (marked with a circle in the figure). When 200 ms has elapsed from the start of the operation, channel 20 and channel 21 are detected as non-communication channels, and channel 12, channel 16, and channel 19 are detected as communication possible channels. At the time when 300 ms elapses from the operation start time, channel 19 and channel 21 are detected as non-communication channels, and channel 11, channel 13, and channel 26 are detected as communication possible channels. As a result, the channel variation table shown in FIG. 7C is stored and held in the control unit 15.

  Next, as shown in FIG. 6B, when the microwave operation detecting means 26 detects the operation start time of the microwave oven 12 after the channel fluctuation table is stored and held (step ST11), when 100 ms elapse ( In step ST12), the channel setting means 21 assigns the communication channels of the wireless communication means 18 to 20 based on the channel fluctuation table (step ST13). That is, the channel setting means 21 assigns one of the communicable channels to the communication channel of the low-speed wireless communication means 20 so that the frequency bands of the communication channels of the wireless communication means 18 to 20 do not overlap, and the frequency of the communication impossible channel Any of a plurality of communication channels not including a band is allocated to the high-speed wireless communication means 18 and the medium-speed wireless communication means 19, respectively. Thereafter, communication channels are assigned at intervals of 100 ms until the operation stop time of the microwave oven 12 is detected in step ST14 (steps ST12 and ST13).

  When the channel fluctuation table of FIG. 7C is stored and held, as shown in FIG. 8, the channel setting unit 21 causes the low-speed wireless communication unit 20 to wait for 100 ms after the start of the operation of the microwave oven 12. Channel 14 is assigned, channel 6 is assigned to high-speed wireless communication means 18, and channel 14 is assigned to medium-speed wireless communication means 19. When 200 ms elapses from the operation start time, channel 12 is assigned to low-speed wireless communication means 20, channel 4 is assigned to high-speed wireless communication means 18, and channel 13 is assigned to medium-speed wireless communication means 19. When 300 ms elapses from the operation start time, channel 11 is assigned to low-speed wireless communication means 20, channel 3 is assigned to high-speed wireless communication means 18, and channel 13 is assigned to medium-speed wireless communication means 19. Since there are a plurality of combinations of communication channels that can be assigned to each of the wireless communication means 18 to 20, an arbitrary combination is assigned.

  Here, the operations from step ST1 to step ST5 are performed by operating the microwave oven 12 on the premises before communicating with the communication device 1. If the channel fluctuation table is created before connecting the communication apparatus 1 to the wireless communication network in this way, the recordable channel and the communication disable channel are microwaves radiated from the installed microwave oven 12. It will be in line with frequency fluctuations.

  If the combination of communication channels to be assigned to each of the wireless communication means 18 to 20 is created in advance as a combination table based on the channel variation table, the channel setting means 21 can assign the communication channel based on the combination table. . Further, since there are a plurality of combinations of communication channels, a plurality of combination tables may be created, and one combination table may be selected with a random number or the like when the operation start time point of the microwave oven 12 is detected.

(Communications system)
Next, a communication system using the communication device 1 will be described. The communication system 40 of this embodiment constructs a communication network using at least three communication devices 1. FIG. 9 is an explanatory diagram showing the topology of each communication network constructed by the power line communication means 17 and the three wireless communication means 18-20.

  As shown in FIG. 9A, when the power cord 3 of each communication device 1 (1) to 1 (5) is plugged into an outlet, the power line communication means 17 of each communication device 1 (1) to 1 (5) is A bus-type power line communication network 41 is constructed between them. Further, as shown in FIG. 9B, the high-speed wireless communication means 18 and the medium-speed wireless communication means 19 communicating with IEEE802.11b / g construct star-type wireless communication networks 42 and 43. As shown in FIG. 9C, the low-speed wireless communication means 20 communicating with ZigBee constructs a mesh-type wireless communication network 44 between them. A server 14 is connected to each of the communication networks 41 to 44.

  According to the communication system 40, the power line communication network 41 and the three wireless communication networks 42 to 44 are constructed. The three wireless communication networks 42 to 44 include star-type wireless communication networks 42 and 43 having different topologies and a mesh-type wireless communication network 44. Therefore, even when the communication environment changes, it is possible to avoid or reduce the case where the communication paths of all the communication networks 41 to 44 are blocked all at once and communication becomes impossible.

  Further, since the mesh-type wireless communication network 44 is constructed by the low-speed wireless communication means 20, and the star-type communication networks 42, 43 are constructed by the high-speed wireless communication means 18 and the medium-speed wireless communication means 19, the communication network A reduction in communication speed due to the topology can be reduced.

  FIG. 10 is a perspective view for explaining an initial setting method for constructing the star-type wireless communication network 42 by the high-speed wireless communication means 18 and the medium-speed wireless communication means 19. As shown in FIG. 10, the power cord 3 is inserted into the power tap 45, and the communication devices 1 (1) to 1 (5) are arranged at a close distance. Further, the setting switch 25 of one communication device 1 (1) is operated to cause the high-speed wireless communication means 18 and the medium-speed wireless communication means 19 of this communication device 1 to function as access points. Then, the high-speed wireless communication unit 18 and the medium-speed wireless communication unit 19 of the communication device 1 (1) acquire the MAC addresses of the other communication devices 1 (2) to (5), and perform star-type wireless communication. Build a network. Then, each communication apparatus 1 (1) -1 (5) is arrange | positioned in the desired place in a campus.

  Note that the access point of the star-type wireless communication network 42 may be the high-speed wireless communication means 18 of the communication device 1 (1), and the access point of the star-type wireless communication network 43 may be the communication device 1 (2). That is, each access point of each star-type wireless communication network 42, 43 can be a different communication device.

  In addition, since the communication standards IEEE802.11b and IEEE802.11g are compatible, the high-speed wireless communication unit 18 and the medium-speed wireless communication unit 19 can construct one wireless communication network. In this case, between the communication device 1 (1) and each of the other communication devices 1 (2) to (5) depending on the response speed when broadcast from the communication device 1 (1) functioning as an access point. Select the communication standard used in. Further, the communication standard selected between the communication device 1 (1) and each of the other communication devices 1 (2) to (5) is stored and held in the communication device 1 (1) functioning as an access point. This makes it easy to restore even if this wireless communication network goes down.

(Effects of the radio interference avoidance unit)
In this example, the channel specifying unit 27 actually detects an interference frequency band that periodically changes as the frequency of the microwave changes as a communication disabled channel of the low-speed wireless communication unit 20 using ZigBee. The elapsed time from the operation start time of the range 12 is associated and stored as a channel fluctuation table. Further, a communicable channel is detected simultaneously with the detection of a communication impossible channel, and is stored and held as a channel fluctuation table in association with the elapsed time. When the channel variation table is stored and held, the channel setting unit 21 communicates with the communicable channel associated with the elapsed time every time the measurement time from the operation start time of the microwave oven 12 becomes the elapsed time. Is set as the communication channel of the low-speed wireless communication means 20. Further, the channel setting means 21 sets a communication channel avoiding the frequency band of the communication impossible channel as a communication channel of the high-speed wireless communication means 18 and the medium-speed wireless communication means 19. Accordingly, the three wireless communication means 18 to 20 can communicate with each other through a communication channel that is not affected by radio wave interference caused by microwaves.

  Further, since the communication channels of the three wireless communication means 18 to 20 are set based on the periodic change of the actually detected interference frequency band, the spectrum distribution and frequency of the microwave generated by the magnetron of the microwave oven 12 are set. Even if there is an individual difference in the fluctuation cycle, wireless communication can always be performed while avoiding the influence of radio wave interference caused by microwaves.

  The channel setting means 21 is set so that the communication channels used by the three wireless communication means 18 to 20 do not overlap the same frequency band. Therefore, communication by the three wireless communication means 18 to 20 does not interfere with each other. Furthermore, since each wireless communication means 18-20 uses a different frequency band, even when radio wave interference occurs in a specific frequency band, it is possible to communicate using other wireless communication means.

  In this example, low-speed wireless communication means 20 that communicates with ZigBee is used to detect the interference frequency band. ZigBee is suitable for detecting an interference frequency band because it has a small transmission output and is susceptible to radio wave interference. Moreover, since ZigBee has a narrow frequency band for each communication channel of 2 MHz, the interference frequency band can be detected with high accuracy.

(Other embodiments)
As the microwave operation detecting means 26, low-speed wireless communication means 20 that communicates with ZigBee can also be used. In this case, frequency hopping is always performed at a predetermined interval by the low-speed wireless communication means 20, and the operation detection means 29 detects the time when radio wave interference occurs in any communication channel as the operation start time of the microwave oven 12, The time when the radio wave interference is eliminated is detected as the operation stop time of the microwave oven 12.

  In the above example, the low-speed wireless communication means 20 that communicates with ZigBee is used to detect the interference frequency band. However, wireless communication means that communicate with other communication standards can also be used. For example, when a wireless communication unit that communicates with Bluetooth is provided, an interference frequency band can be detected by detecting a communication impossible channel using the wireless communication unit.

  In the above example, the communication device 1 includes the three wireless communication units 18 to 20. However, the present invention can be applied to a communication device including only one wireless communication unit. In this case, it is only necessary to perform frequency hopping by this wireless communication means to detect a communicable channel and a non-communication channel, and store and hold the channel variation table.

  In the above example, the communication status monitoring unit 22 monitors whether or not the communication speed of the communication unit that is performing communication falls below the allowable speed, but the communication state of the communication unit that is performing communication is monitored. Communication quality may be monitored. For example, the error rate is detected, and it is monitored whether or not the error rate falls below a predetermined allowable rate. In this case, when the error rate exceeds a preset allowable error rate, the communication control unit 23 changes one communication unit performing communication to the communication unit having the next highest communication speed according to the communication standard. Switch. In this way, highly reliable communication can be performed. Note that the SNR may be detected as the communication quality.

  In the above example, the communication control means 23 causes the power line communication means 17 and any one of the three wireless communication means 18 to 20 to perform communication, but the communication control means 23 is the power line communication means 17. And you may make it make all the three radio | wireless communication means 18-20 perform the same communication. If the same data is transmitted / received by all the communication means, even if a part of the data is lost due to deterioration of the communication environment, the transmitted / received data can be selected or synthesized by a well-known technique to complement the missing part.

  In this case, the communication state monitoring unit 22 monitors whether or not the communication speeds of the power line communication and the three wireless communication units 18 to 20 are below the permissible speeds, and the communication control unit 23 is connected to the communication speed. If a communication means that has fallen below the allowable speed is detected, if the detected communication means is not the low-speed wireless communication means 20 by ZigBee that has the slowest communication speed in accordance with the communication standard, communication of the detected communication means is performed. You may make it stop.

  FIG. 11 is an explanatory view schematically showing an operation in which the communication control means 23 stops communication when the communication speed falls below the allowable speed. As shown in FIG. 11, when the communication speed of the high-speed wireless communication means 18 falls below the allowable speed, the communication by the high-speed wireless communication means 18 is stopped, and the power line communication means 17, the medium-speed wireless communication means 19, the low-speed wireless communication The unit 20 performs communication. When the communication speed of the power line communication means 17 falls below the allowable speed, communication by the power line communication means 17 is stopped and the medium speed wireless communication means 19 and the low speed wireless communication means 20 are made to communicate. When the communication speed of the medium-speed wireless communication unit 19 falls below the allowable speed, the communication by the medium-speed wireless communication unit 19 is stopped and the low-speed wireless communication unit 20 performs communication. When communication is performed by the low-speed wireless communication unit 20, the communication by the low-speed wireless communication unit 20 is maintained. In this way, it is possible to eliminate communication whose communication state has deteriorated due to changes in the communication environment.

  In the above example, the communication device 1 and the device are configured as separate bodies. However, the communication device 1 may be configured to be separated from the device inside the device.

  In addition, the communication device 1 can include an auxiliary battery and a memory. In this way, communication is possible even during a power failure. In addition, the device received via the communication network can be temporarily stored in the memory and transmitted to the device after the power is restored. Further, the communication device 1 can be provided with the function of an uninterruptible communication device. Alternatively, the power supply unit 10 may be removed from the communication device 1.

  In the communication system 40 described above, a communication network is constructed using at least three communication devices 1, but communication may be performed between the two communication devices 1.

It is an external appearance perspective view of the communication apparatus which concerns on this Embodiment. It is a block diagram of a communication apparatus. It is explanatory drawing of the communication channel used by a wireless communication means. It is explanatory drawing which shows typically the operation | movement which a communication control means switches a communication means. It is explanatory drawing which shows the structural example of a microwave oven operation | movement detection part. It is a flowchart which shows the operation | movement for avoiding radio wave interference. It is explanatory drawing of the communication possible channel detected and a communication impossible channel. It is explanatory drawing which shows the example to which the communication channel was allocated. It is explanatory drawing which shows the topology of the communication network which each communication means construct | assembles. It is a perspective view for demonstrating the method of initial setting. It is explanatory drawing which shows another example of the operation | movement which a communication control means switches a communication means.

Explanation of symbols

1. Communication device 2. Printer 3. Power cord 4. Device body 5. Connection cord 6. Communication connector 7. Power connector 8. Power line 10. Power supply unit 11. Communication unit 12. · Microwave oven, 13 · Radio interference avoidance unit, 14 · Server, 15 · Control unit, 16 · Communication means, 17 · Power line communication means, 18 · High-speed wireless communication means, 19 · Medium-speed wireless communication means, 20 · Low-speed wireless Communication means, 21 channel setting means, 22 communication state monitoring means, 23 communication control means, 24 drive control means, 25 setting switch, 26 microwave operation detecting means, 27 channel specifying means (frequency band specifying) Means), 28. Voltage fluctuation detection means, 29. Operation detection means, 30. Induction coil, 31. Transmission means, 41. Power line communication network, 42, 43. Star type wireless communication network, 4 mesh type wireless communications network, 45, power strips

Claims (16)

After detecting the operation start time of the magnetron, the interference frequency band in which the radio wave is generated is detected until the operation stop time of the magnetron is detected, and the interference frequency band and the interference frequency band are determined from the operation start time. A frequency band specifying step for storing and holding the elapsed time until detection in a correlated form;
The time from when the operation start time of the magnetron is detected to when the operation stop time is detected is measured, and when the measurement time reaches the elapsed time, the interference frequency band associated with the elapsed time And a channel setting step for setting a communication channel that avoids interference. In the radio wave interference avoidance method of the wireless communication device according to claim 1,
In the frequency band specifying step, the communication disabled channel that cannot be communicated is detected by causing the first communication means that performs communication in the specified frequency band to perform frequency hopping at predetermined intervals, and the communication disabled channel is set as the interference frequency band. A method for avoiding radio wave interference in a wireless communication device, characterized by storing and holding the data. In the radio wave interference avoidance method of the wireless communication device according to claim 2,
In the frequency band specifying step, a communicable channel that can be communicated simultaneously with the detection of the incommunicable channel is detected, and the incommunicable channel, the communicable channel, and the elapsed time are stored and retained in association with each other. ,
In the channel setting step, when the measurement time reaches the elapsed time, the communicable channel associated with the elapsed time is set as a communication channel of the first communication unit. How to avoid radio interference. In the radio wave interference avoiding method of the wireless communication device according to claim 3,
In the channel setting step, when setting the communication channel of the second communication means different from the first communication means, setting is performed so as not to overlap the frequency band of the communication channel of the first communication means. A method for avoiding radio wave interference in a wireless communication device. In the method for avoiding radio wave interference of the wireless communication device according to any one of claims 2 to 4,
The radio communication apparatus radio wave interference avoidance method, wherein the first communication means is a weak radio system. In the radio wave interference avoiding method for a wireless communication device according to any one of claims 1 to 5,
Including a sensor installation process for attaching an induction coil to the power cord of the magnetron built-in device,
In the frequency band specifying step and the channel setting step, the operation start time and the operation stop time are detected based on an electrical change generated in the induction coil. In the radio wave interference avoiding method for a wireless communication device according to any one of claims 1 to 5,
Including a sensor installation step of attaching voltage fluctuation detection means to the power line to detect a change in power supply voltage of the power line that supplies power to the magnetron built-in device,
In the frequency band specifying step and the channel setting step, a radio wave interference avoiding method for a radio communication apparatus, wherein an operation start time and an operation stop time of the magnetron are detected based on a change in the power supply voltage. In the radio wave interference avoidance method of the wireless communication device according to claim 5,
In the frequency band specifying step and the channel setting step, the first communication means performs frequency hopping at the predetermined interval, and the time when the communication-disabled channel is first detected is detected as the operation start time. A method of avoiding radio wave interference in a wireless communication apparatus, wherein a time point when a channel is not detected is detected as the operation stop time point. Operation detecting means for detecting the operation start time and operation stop time of the magnetron;
The interference frequency band in which radio waves are generated is detected from the operation start time to the operation stop time, and the interference frequency band is associated with the elapsed time from the operation start time to the detection of the interference frequency band. Frequency band specifying means for storing and holding in a
When the interference frequency band and the elapsed time are stored and held in association with each other, the time from the operation start time to the operation stop time is measured, and when the measurement time reaches the elapsed time, the elapsed time And a channel setting unit that sets a communication channel that avoids the interference frequency band associated with time. The wireless communication device according to claim 9, wherein
Having a first communication means of a communication standard for communication in a specific frequency band;
The frequency band specifying unit detects a communication impossible channel by causing the first communication unit to perform frequency hopping at a predetermined interval, and stores and holds the communication disabled channel as the interference frequency band. A wireless communication device. The wireless communication device according to claim 10, wherein
The frequency band specifying means detects a communicable channel that can communicate simultaneously with the detection of the communication impossible channel, and stores and holds the communication disabled channel and the communicable channel in association with the elapsed time. ,
The channel setting means sets the communicable channel associated with the elapsed time as the communication channel of the first communication means when the measured time reaches the elapsed time. The wireless communication device according to claim 11, wherein
A second communication means different from the first communication means;
The wireless communication apparatus, wherein the channel setting means sets the communication channel of the second communication means so as not to overlap with the frequency band of the communication channel of the first communication means. In the wireless communication device according to any one of claims 10 to 12,
A wireless communication apparatus characterized in that a communication standard of the first communication means is a weak wireless system. In the wireless communication device according to any one of claims 9 to 13,
Has an induction coil attached to the power cord of the magnetron built-in device,
The wireless communication apparatus, wherein the motion detection means detects the motion start time and the motion stop time based on an electrical change generated in the induction coil. In the wireless communication device according to any one of claims 9 to 13,
Voltage fluctuation detection means attached to the power line for detecting a change in power supply voltage of the power line supplying power to the magnetron built-in device,
The wireless communication apparatus, wherein the operation detection unit detects the operation start time and the operation stop time based on a change in the power supply voltage. The wireless communication device according to claim 13, wherein
The operation detection unit causes the first communication unit to perform frequency hopping at the predetermined interval, detects a time when the communication disabled channel is first detected as the operation start time, and the communication disabled channel is not detected. A wireless communication apparatus that detects a time point as the operation stop time point.

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