JP5351836B2 - Wireless communication apparatus and wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase effective communication speed by using a plurality of frequency channels for a radio communication signal and to improve communication reliability by suppressing interference. <P>SOLUTION: A radio communication system performs radio communication between a first group formed by a plurality of radio communication devices using a first frequency channel and a second group formed by a plurality of radio communication devices using a second frequency channel. At least two radio communication devices can switch to use the first frequency channel or the second frequency channel and include a function for sending a channel switchover signal after performing switchover control of a frequency channel in which the own device uses when having detected a channel changeover condition, and a function for controlling by switching a frequency channel in which the own device uses by determining that a received channel changeover signal is destined to the own device. When one radio communication device uses a first frequency channel, another radio communication device is configured to use the second frequency channel. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a wireless communication apparatus and a wireless communication system.

  Conventionally, the usage fee for electricity, gas, water, and other usage periods is based on the meter reading the meter of electricity, gas, water, etc. installed in the house on a regular basis and recording the meter value. Thus, it has been calculated based on the difference from the previous meter reading value. However, it is a problem that the human cost of the meter reader is high and it may be difficult to deal with when the resident of the house (administrator, etc.) is absent, and the usage amount of electricity, gas, water, etc. A system for automating the meter reading work has been developed.

  For example, in the prior art described in Patent Document 1, a method of using wireless communication for an automatic meter reading system is disclosed. In this automatic meter reading system, a wireless device having a meter reading function is arranged so that a communication path between the wireless devices is in a tree shape, a meter reading value is transmitted wirelessly, and an aggregation device located at the top of the tree is provided. Collect meter readings. Then, when the periodic meter reading value does not reach from each wireless device, the aggregation device transmits a signal for requesting retransmission to the corresponding wireless device, and collects the meter reading value from the wireless device.

  In addition, the conventional technique described in Patent Document 2 discloses a method of performing channel access using a plurality of frequency channels in an autonomous distributed wireless communication network that does not require a specific control station. A plurality of wireless communication devices constituting a wireless communication network broadcast beacon information including seed information that is a basis for determining the beacon transmission timing and transmission channel of the local station, and receive from other stations when newly entering the network Identify the channel switching pattern for beacon transmission on each channel based on the seed information in the beacon information, select the available beacon transmission timing and transmission channel candidates, and select the beacon information Send.

JP 2009-14184 A JP 2005-45637 A

  However, the prior art described in Patent Document 1 performs wireless communication using a single frequency channel. When performing multi-hop communication in a tree-shaped network as described in Patent Document 1, if only a single frequency channel is used, the transmission timing of communication signals for each hop is divided in time to collide. There is a problem that effective communication speed is reduced.

  In addition, when using CSMA / CA (Carrier Sense Multiple Access / Collection Aidance), which is an access control method that avoids collision by detecting signal strength without separating transmission timing of communication signals in time As the number of wireless communication devices increases, communication signals are more likely to collide, and there is a problem that communication reliability is reduced.

  Moreover, in the prior art described in Patent Document 2, it is necessary for a plurality of wireless communication apparatuses to notify each other's beacon transmission timing and transmission channel and to synchronize the beacon transmission timing and transmission channel. However, in order to receive a beacon transmitted by another wireless communication device, the receiving wireless communication device needs to change to the frequency channel at the same time, and a complicated time synchronization technique is required.

  In a wireless network composed of a large number of wireless communication devices, it is possible to use a method for improving communication efficiency by using multicast communication that transmits information with a single signal to a plurality of wireless communication devices. However, in the prior art described in Patent Document 2, each wireless communication device uses a different frequency channel for each time, and thus there is a problem that it is difficult to improve communication efficiency using multicast communication.

  Therefore, in the present invention, a wireless communication device and a wireless communication device that can improve multicast communication for improving communication efficiency while improving effective communication speed, suppressing interference and improving communication reliability. A communication system is provided.

A wireless communication device of the present invention includes an antenna for wireless communication, a wireless communication unit that executes wireless communication signal processing, a communication control unit that controls wireless communication, and a channel switching control unit that switches a frequency channel of the wireless communication signal A channel switching condition detecting unit for detecting a condition for switching the frequency channel, a channel switching signal generating unit for giving a channel switching signal transmission instruction, and an instruction for the channel switching signal received via the antenna addressed to the own station. A channel switching signal determination unit for determining that there is,
The channel switching control unit controls the frequency channel of the local radio communication unit based on signals input from the channel switching condition detection unit and the channel switching signal determination unit, and the channel switching control unit sets the channel switching signal generation unit to It has a function of driving and transmitting a channel switching signal to the other end.

A wireless communication device of the present invention includes an antenna for wireless communication, a wireless communication unit that executes wireless communication signal processing, a communication control unit that controls wireless communication, and a channel switching control unit that switches a frequency channel of the wireless communication signal A channel switching condition detecting unit for detecting a condition for switching the frequency channel, a channel switching signal generating unit for giving a channel switching signal transmission instruction, and an instruction for the channel switching signal received via the antenna addressed to the own station. A channel switching signal determination unit for determining that there is,
The channel switching control unit controls the frequency channel of the wireless communication unit based on the signal input from the channel switching condition detection unit, and then drives the channel switching signal generation unit to give a transmission instruction for the channel switching signal. The switching signal determination unit has a function of controlling the frequency channel of the wireless communication unit when it is determined that the channel switching signal received via the antenna is an instruction addressed to the own station.

  When the channel switching signal determination unit determines that the channel switching signal received via the antenna is an instruction addressed to the own station, the channel switching response signal is received as a response indicating that the channel switching signal has been received. It is preferable to have a function of transmitting through the wireless communication unit and controlling the frequency channel of the wireless communication unit.

  In addition, it is preferable to retransmit the channel switching signal when the channel switching response signal is not received within a predetermined time from the transmission of the channel switching signal.

The wireless communication system of the present invention includes a first group formed by a plurality of wireless communication devices using a first frequency channel and a second group formed by a plurality of wireless communication devices using a second frequency channel. A wireless communication system for performing wireless communication with a group of:
At least two wireless communication apparatuses can switch between the first frequency channel and the second frequency channel, and when the channel switching condition is detected, switch the frequency channel used by themselves, and then transmit the channel switching signal. A function and a function of determining that the received channel switching signal is a signal addressed to the own station and controlling switching of the frequency channel used by itself, and when one of the wireless communication apparatuses uses the first frequency channel In addition, the other wireless communication apparatus uses the second frequency channel.

  When it is determined that the received channel switching signal is an instruction addressed to its own station, a channel switching response signal is transmitted as a response indicating that the channel switching signal has been received, and switching control of the frequency channel used by itself is performed. It is good to do.

  In addition, it is preferable to retransmit the channel switching signal when the channel switching response signal is not received within a predetermined time from the transmission of the channel switching signal.

The wireless communication system of the present invention includes a first group formed by a plurality of wireless communication devices using a first frequency channel and a second group formed by a plurality of wireless communication devices using a second frequency channel. A wireless communication system for performing wireless communication with a group of:
At least two wireless communication devices can switch between the first frequency channel and the second frequency channel, and the first wireless communication device switches and controls the frequency channel used by itself when the channel switching condition is detected. Later, it has a function of transmitting a channel switching signal, and the second wireless communication apparatus has a function of determining that the received channel switching signal is a signal addressed to its own station and switching control of the frequency channel used by itself. And when one wireless communication device uses the first frequency channel, the other wireless communication device uses the second frequency channel.

  In addition, two or more second wireless communication devices are provided, and each second wireless communication device determines the frequency channel used by itself when it determines that the received channel switching signal is an instruction addressed to itself. It is preferable to have a function of switching control and transmitting a channel switching signal to another second wireless communication apparatus.

The wireless communication system of the present invention includes a first group formed by a plurality of wireless communication devices using a first frequency channel and a second group formed by a plurality of wireless communication devices using a second frequency channel. A wireless communication system for performing wireless communication between the group and a third group formed by a plurality of wireless communication devices using a third frequency channel,
At least two first wireless communication devices are provided for performing wireless communication between the first group and the second group, and the first wireless communication device includes a first frequency channel and a second frequency channel. The function to transmit the channel switching signal after switching control of the frequency channel used by itself when the channel switching condition is detected, and the received channel switching signal is a signal addressed to the own station And when one radio communication device uses the first frequency channel, the other radio communication device uses the second frequency channel. With
At least two second wireless communication devices are provided for performing wireless communication between the second group and the third group, and the second wireless communication device includes the second frequency channel and the third group. The function to transmit the channel switching signal after switching control of the frequency channel used by itself when the channel switching condition is detected, and the received channel switching signal is a signal addressed to the own station And when one of the wireless communication apparatuses uses the second frequency channel, the other wireless communication apparatus uses the third frequency channel. I did it.

  The wireless communication device is preferably installed in the meter-reading device of the meter-reading target facility and wirelessly communicates the meter-reading data.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the radio | wireless communication apparatus which can suppress interference by using a some frequency channel by a simple method. Further, it is possible to provide an automatic meter reading system that can improve the effective communication speed by suppressing interference by using a plurality of wireless communication apparatuses according to the present invention. Furthermore, it is possible to make communication more efficient by using multicast communication together.

1 is a diagram illustrating an example of a configuration of a wireless communication device. The figure which shows the example of installation of a unit type watt-hour meter, and an example of a circuit structure. The figure which shows an example of the frequency channel arrangement | positioning of radio | wireless communication. The figure which shows the whole structure of the automatic meter-reading system to which this invention is applied. The figure which shows an example of a structure of an aggregation apparatus. The figure which shows an example of the switching of the frequency channel of a switching terminal. The figure which shows the 1st Example of a frequency channel switching process. The flowchart which shows the frequency channel switching method of FIG. The figure which shows the 2nd Example of a frequency channel switching process. FIG. 10 is a flowchart showing the frequency channel switching method of FIG. 9. The figure which shows the 3rd Example of a frequency channel switching process. FIG. 12 is a flowchart showing the frequency channel switching method of FIG. 11. The figure which shows the whole structure of the automatic meter-reading system which uses three frequency channel switching terminals. The figure which shows the 4th Example of a frequency channel switching process. The flowchart which shows the frequency channel switching method of FIG. The figure which shows an example of the automatic meter-reading system which uses three frequency channels.

  Next, modes for carrying out the present invention will be described in detail with reference to the drawings as appropriate.

  The overall configuration of an automatic meter reading system to which the present invention is applied is shown in FIG. This automatic meter reading system includes a plurality of terminals 1a, 1b, 1c, 1d, 1e and an aggregation device 2. Then, the electricity usage amount of each household collected in the aggregation device 2 is sent to a power company (not shown) via the backbone network 5. The meter reading target of the present system may be gas, water supply, or the like, but here, an example of power meter reading will be described.

  Terminals 1a, 1b, 1c, 1d, and 1e are unit-type watt-hour meters 1 installed in each home that are the targets of automatic meter reading. A circuit configuration will be described.

  Further, the aggregation device 2 will be described separately with reference to FIG.

  Further, the terminal 1 and the aggregation device 2 are equipped with a wireless communication device 10 for realizing communication between these devices, and the wireless communication device 10 will be separately described with reference to FIG.

  First, in FIG. 2, terminal 1 (unit-type watt-hour meter) is a low-voltage distribution line on which a voltage converted into a low voltage by transformer 22 is superimposed from high-voltage distribution line 21 on which a commercial AC high voltage is superimposed. A plurality of terminals 23 are connected. Generally, about 10 to 20 unit-type watt-hour meters 1 are connected to one transformer 22.

  Here, the transformer 22 is a so-called pole transformer, and the aggregation device 2 is often installed at the position of the pole transformer. The unit-type watt-hour meter 1 is provided in each home as a unit for paying the electric power charge, and supplies power to the distribution board 24 of each home 25 via the unit-type watt-hour meter 1.

  The unit watt-hour meter 1 includes a power amount measuring unit 30, a switch 40, and a wireless communication device 10. The power amount measurement unit 30 measures an amount (power amount) obtained by temporally integrating power, and outputs the measured value (meter reading value) toward the aggregation device 2 via the wireless communication device 10. When the switch 40 is turned off based on a signal output from the wireless communication device 10, the switch 40 cuts off the power supply to the house 25 through the distribution board 24 at a time.

  The wireless communication device 10 transmits the measurement value received from the power amount measurement unit 30 by wireless communication (for example, 2.4 GHz band or 950 MHz band). The signal transmitted and received by the wireless communication device 10 includes not only a result of examination of household power consumption but also a generated power such as solar power generation in each household, that is, a result of meter reading of the amount of power sold. In addition, an open / close state signal or an operation signal of the switch 40 in each home is included, and not only mere meter reading but also a monitoring / control operation of the switch 40 can be executed.

  Note that signal transmission from the unit-type watt-hour meter 1 to the aggregation device 2 (hereinafter, signal transmission in this direction is referred to as an upward direction and the reverse direction is referred to as a downward direction) is performed between a plurality of unit-type watt-hour meters 1. In accordance with the order determined in advance, it can be performed at a constant cycle, or it can be performed in response to a transmission command from the aggregation device 2. Alternatively, it is also possible to detect the idle state of communication and transmit its own data.

  As shown in FIG. 5, the aggregation device 2 includes a wireless communication device 10 and a backbone network interface 50, and data input from the backbone network 5 is converted by the wireless communication device 10 via the backbone network interface 50 into unit power consumption. It has a function of outputting data from the unit watt-hour meter 1 transmitted to the total 1 and received by the wireless communication device 10 to the backbone network 5 via the backbone network interface 50. The backbone network 5 may be an optical fiber, a metal line, or wireless communication.

  As described above, the plurality of terminals 1 and the aggregation device 2 which are main devices constituting the automatic meter reading system constitute a network by the wireless communication device 10 and perform signal transmission.

  Next, the configuration of the wireless communication device 10 according to the present embodiment will be described with reference to FIG. The wireless communication device 10 includes a wireless communication unit 11, a channel switching control unit 12, a channel switching condition detection unit 13, a storage unit 14, a communication control unit 15, a channel switching signal determination unit 16, a channel switching signal generation unit 17, and an input / output interface. Unit 18, power supply unit 19, and antenna 20.

  Among these, the communication control unit 15 stores data input / output from / to the outside in the input / output interface unit 18 in the storage unit 14 or controls the wireless communication unit 11 to convert the data into data for wireless communication. It has a function to do.

  The communication control unit 15 generally corresponds to a central processing unit CPU (Central Processing Unit), but may be configured by a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or the like.

  The storage unit 14 is generally composed of a memory such as an SRAM (Static Random Access Memory) or a DRAM (Dynamic Random Access Memory).

  The input / output interface unit 18 is generally configured by a wired, wireless, infrared interface, or the like such as Ethernet (registered trademark), RS232C, or IrDA.

  When the wireless communication device 10 is used as the unit-type watt-hour meter of FIG. 2, the input / output interface unit 18 obtains the electric energy from the electric energy measurement unit 30 and obtains the open / closed state of the switch 40. It performs functions such as giving an open / close operation signal. Further, when the wireless communication device 10 is used as the aggregation device 2 in FIG. 5, it is connected to the backbone network interface 50 and used. It should be noted that a plurality of input / output interface units 18 can be provided as appropriate according to the situation of the application target where the wireless communication device 10 is installed.

  The wireless communication unit 11 transmits a wireless communication signal via the antenna 20 based on the data input from the communication control unit 15. A wireless communication signal input via the antenna 20 is received by the wireless communication unit 11 and output to the communication control unit 15.

  The wireless communication unit 11 is usually configured by a circuit used in wireless communication such as modulation / demodulation, a frequency converter, a filter, and a high frequency switch. At this time, the frequency channel used for transmission and reception of the wireless communication signal in the wireless communication unit 11 is selected by the channel switching control unit 12 and based on the control signal 121 input from the channel switching control unit 12 to the wireless communication unit 11. It is determined.

  The channel switching control unit 12 determines the control signal 121 based on the signal 201 from the channel switching condition detection unit 13 and the signal 123 from the channel switching signal determination unit 16 and selects a frequency channel to be used in the wireless communication unit 11. . The frequency channel selection method will be described later.

  The channel switching signal determination unit 16 inputs a signal input to the communication control unit 15 via the wireless communication unit 11 or the input / output interface unit 18, extracts the channel switching signal 123 from the signal, and selects the channel switching control unit 12 is driven.

  Further, the channel switching signal generation unit 17 outputs a channel switching signal output to the wireless communication unit 11 or the input / output interface unit 18 to the communication control unit 15 based on the signal 122 input from the channel switching control unit 12.

  The operating condition of the channel switching condition detection unit 13 can be set as appropriate. For example, the channel switching signal 201 may be generated at a predetermined time using a timer. Alternatively, the condition may be that the channel switching signal 201 is generated when the number of times of wireless communication reaches a certain number.

  In the present embodiment, the channel switching control unit 12, the channel switching condition detection unit 13, the channel switching signal determination unit 16, and the channel switching signal generation unit 17 have been described as separate functional blocks in order to simplify the description. In a normal wireless communication apparatus, these functions are often mounted on the same components as the central processing unit CPU that constitutes the communication control unit 15, and the plurality of functions are realized by software.

  The wireless communication device 10 has the configuration of FIG. 1 as a standard, but the wireless communication devices 10 in all the terminals 2 of the network of FIG. 4 do not always use these functions. Depending on the role to be played, some or all of the functions are appropriately selected and used.

  In particular, the functions of the channel switching control unit 12, the channel switching condition detection unit 13, the channel switching signal determination unit 16, and the channel switching signal generation unit 17 are provided as standard, and by selectively using these functions, It is possible to contribute to the configuration of the network of FIG. 4 that can achieve the three problems of the invention (improvement of effective communication speed, improvement of reliability by suppressing interference, and improvement of communication efficiency).

  The power supply unit 19 has a function of converting from a power source such as AC 100 V supplied from the outside into a plurality of power sources used in the wireless communication apparatus 10, for example, DC 5 V, and supplying the power to each unit.

  The automatic meter reading system whose entire configuration is shown in FIG. 4 is configured by using the apparatus shown in FIGS. 1, 2, and 5. However, in the wireless communication used here, it can be used for communication by the radio wave method. The frequency is specified.

  As shown in FIG. 3, a plurality of frequency channels having center frequencies such as f1, f2, f3, f4, and f5 on the frequency axis and having a certain frequency width are provided. In FIG. 3, a plurality of frequency channels CH1, channel CH2, channel CH3, channel CH4, channel CH5, and the like exist. For example, in the 950 MHz band, 24 frequency channels having a frequency width of 200 kHz are provided.

  In the automatic meter reading system to which the present invention is applied, the three problems of the present invention (improvement of effective communication speed and improvement of reliability by suppressing interference) are provided under the above-described wireless communication equipment and a prescribed frequency environment. , Improve communication efficiency).

  In the present invention, when the automatic meter-reading system of FIG. 4 is configured, the first object “improvement of effective communication speed” and the second problem “improving reliability by suppressing interference” are aimed at. Thus, grouping of wireless communication devices and multi-frequency channeling are performed.

  Specifically, the aggregation device 2, the terminal 1a, and the switching terminals 1b and 1c are assumed to belong to the group 4a that uses the first frequency channel CH1. Similarly, the switching terminals 1b and 1c and the terminals 1d and 1e belong to the group 4b that uses the second frequency channel CH2.

  Here, it is important in the present invention that the groups 4a and 4b use different frequency channels. Since the wireless communication signals in each group do not interfere with the wireless communication signals in the other groups, the reliability is high and the effective communication speed in the entire automatic meter reading system can be improved.

  Although the terminals 1b and 1c are referred to as switching terminals, this is for convenience of explanation, and the configuration of the apparatus may be the same as that of the other terminals 1a, 1d, and 1e as shown in FIG. The difference between the other terminals 1a, 1d, and 1e and the switching terminals 1b and 1c is that the former is used with the frequency channel fixed to either the first or second frequency channel CH1 or CH2. The latter is different in that the first and second frequency channels CH1 and CH2 are appropriately switched and used.

  This will be described with reference to the configuration of the wireless communication device 10 in FIG. 1. First, all the terminals 1 have the configuration of the wireless communication device 10. Then, the other terminals 1a, 1d, and 1e are provided with a standard configuration related to channel switching (functions of the channel switching control unit 12, the channel switching condition detection unit 13, the channel switching signal determination unit 16, and the channel switching signal generation unit 17). ) Is not used (does not function), the switching terminals 1b and 1c actively use the configuration related to channel switching.

  However, since the groups 4a and 4b use different frequency channels if they are simply grouped, it is usually difficult to transmit data to each other by wireless communication. For example, assuming that data transmitted by the aggregation device 2 is transmitted to the terminal 1e by multi-hop wireless communication, wireless communication is performed on the first frequency channel CH1 from the aggregation device 2 to the switching terminal 1b via the terminal 1a. However, since the terminal 1d uses the second frequency channel CH2, data cannot be transmitted to the terminal 1e via the terminal 1d.

  Therefore, the switching terminals 1b and 1c switch the frequency channels alternately between a plurality of frequency channels in order to enable wireless communication between the groups 4a and 4b.

  The facility for enabling this switching is provided in the wireless communication apparatus 10 as described in FIG. That is, the channel switching control unit 12 is provided that can switch and use the frequency channel used for transmission and reception of the wireless communication signal as appropriate. Based on the signals input from the channel switching condition detection unit 13 and the channel switching signal determination unit 16, the channel of the local station can be switched, and the channel switching of the other station can be performed via the channel switching signal generation unit 17. It is configured to be able to instruct.

  The switching terminals 1b and 1c execute communication across the group 4 using the devices and functions configured as described above as shown in FIG. Specifically, the switching terminals 1b and 1c appropriately switch between the wireless communication channel CH1 for the group 4a and the wireless communication channel CH2 for the group 4b.

  For example, when the channel switching condition detection unit 13 detects the switching condition 201a while executing the communication 101a for the group 4a using the channel CH1, the channel switching control unit 12 acts on the wireless communication unit 11, Switch to the communication 102a for the group 4b that uses the channel CH2. Further, when the channel switching condition detection unit 13 detects the switching condition 201b during the execution of the communication 102a, the channel switching control unit 12 acts on the wireless communication unit 11 to perform communication for the group 4a that uses the channel CH2 again. And the new communication 101b is executed.

  Here, the channel switching is executed as shown in FIG. 6, but the information transmitted by the switching terminals 1b and 1c in each communication is the content of the communication performed using another channel in the previous stage. For example, the communication content at the time of communication 101b using channel CH1 is the communication content at the time of communication 102a using channel CH2 before that. This means that the contents transmitted to the upstream by the terminals 1d and 1e of the group 4b through the communication 102a are transmitted to the aggregation device 2 of the group 4a through the communication 101b.

  Similarly, the communication content at the time of communication 102a using channel CH2 is the communication content at the time of communication 101a using channel CH1. This means that in the communication 101a, the switching terminals 1b and 1c transmit the content transmitted by the aggregation device 2 of the group 4a downstream in the communication 101a toward the terminals 1d and 1e of the group 4b.

  Summarizing the results, for example, the contents transmitted to the downstream terminals by the aggregation device 2 through the communication 101a can be received by the terminals 1a, 1b and 1c in the group 4a within this period, and further necessary. The response can be within this period. On the other hand, the terminals 1d and 1e in the group 4b receive via the communication 102a via the switching terminals 1b and 1c. Therefore, even if the necessary response can be made within the period of the communication 102a, it reaches the switching terminals 1b and 1c, and the response reaches the aggregation device 2 by the communication 101b. Such communication causes a time delay to some groups, but achieves vertical communication.

  As is clear from this, switching from the channel CH2 to the channel CH1 means that the uplink PU in FIG. 4 has been formed. Conversely, switching from channel CH1 to channel CH2 means that the downlink PD in FIG. 4 has been formed.

  The channel switching condition can be set as appropriate. For example, the channel switching condition may be set such that the channel is switched at a predetermined time using a timer. Or you may make it the conditions of switching, when the frequency | count of radio | wireless communication reaches a fixed frequency.

  Thus, for example, by switching the frequency channel of the switching terminal every time, wireless communication can be performed with terminals belonging to the group 4a during the period set in the frequency channel CH1, and the frequency channel CH2 is set. During this period, it is possible to perform wireless communication with terminals belonging to the group 4b.

  In this way, the switching terminal can wirelessly communicate with terminals belonging to a plurality of groups by switching the frequency channel every time. However, depending on the time, terminals in a group using a frequency channel different from the frequency channel used by the switching terminal cannot perform wireless communication with the switching terminal. That is, if the system of FIG. 6 is used as it is, the purpose of “improving communication efficiency” which is the third problem of the present invention cannot be sufficiently achieved.

  For this reason, in the present invention, as shown in FIG. 4, two switching terminals 1b and 1c are provided at the boundary between the groups 4a and 4b. Channel switching signals 3a and 3b are transmitted between the switching terminals 1b and 1c. As a result, when one switching terminal is communicating for one group, the other switching terminal is communicating for the other group. As a result, it is possible to realize a situation where bidirectional communication is always performed as the entire system.

  A first embodiment of the frequency channel switching process for realizing always bidirectional communication using the switching terminals 1b and 1c will be described with reference to FIG. 7 shows the operation of the switching terminal 1b, and the lower part shows the operation of the switching terminal 1c.

  In describing the switching operation, in the initial state, the switching terminal 1b executes the communication 102b using the channel CH2 for the group 4b, and at the same time, the switching terminal 1c uses the channel CH1 for the group 4a to perform the communication 101d. Is assumed to be executed.

  In this state, the channel switching control unit 12 in the switching terminal 1b detects the switching condition detection signal 201c for switching the channel from the channel switching condition detection unit 13, and acts on the radio communication unit 11 to Channel switching is executed at time t1. As a result, the frequency channel of the switching terminal 1b is changed from the channel CH2 to the channel CH1, and the communication content is changed from 102b to 101c.

  After switching to channel CH1, the channel switching control unit 12 in the switching terminal 1b sends the signal 122 to the channel switching signal generation unit 17 and acts on the communication control unit 15 to add some of the data to be transmitted to other stations. Communication including a channel switching signal for instructing channel switching at the station is executed. Communication at this time is performed using the channel CH1, and a channel switching signal 3a designating the switching terminal 1c is transmitted as another station.

  This signal 3a is received by the terminals and aggregation devices in the group 4a. In this state, since the switching terminal 1c is using the channel CH1, it can receive the channel switching signal 3a. When the channel switching signal determination unit 16 in the switching terminal 1c determines that the channel switching signal 3a included in the received data of the communication control unit 15 is an instruction addressed to the own station, the signal 123 is sent to the channel switching control unit 12. It acts on the wireless communication unit 11 to change its own frequency channel from channel CH1 to channel CH2 at time t2. Then, the communication content is changed from 101d to 102d.

  The above operation between the plurality of switching terminals 1 is the configuration related to channel switching of the wireless communication device 10 (functions of the channel switching control unit 12, the channel switching condition detection unit 13, the channel switching signal determination unit 16, and the channel switching signal generation unit 17). This is achieved by the operation of each part in the above procedure by the mutual action of For this reason, in the following description of the present invention, unless specifically required, only the event that is achieved as a result will be described, and a detailed operation description of the configuration relating to channel switching will be omitted.

  Thereafter, the switching terminal 1c continues communication on the channel CH2, but when the switching condition detection signal 201d is detected, the switching is performed at time t3. As a result, the frequency channel of the switching terminal 1c is changed from the channel CH2 to the channel CH1, and the communication content is changed from 102d to 101e.

  After changing to channel CH1, switching terminal 1c transmits channel switching signal 3b. This signal 3b is received by the terminals in the group 4b. In this state, since the switching terminal 1b is using the channel CH1, it can receive the channel switching signal 3b. When the switching terminal 1b receives the channel switching signal 3b and determines that the channel switching signal is an instruction addressed to the own station, the switching terminal 1b changes the frequency channel from the channel CH1 to the channel CH2 at time t4, and the communication content is changed from 101c. 102c.

  As described above, the two switching terminals 1b and 1c normally communicate with each other using the channel CH1 and the other uses the channel CH2. When the channel switching condition 201 is detected, the switching terminals 1b and 1c are first assigned their own channels. Switch to match the other channel to ensure communication. Then, the channel switching signal 3 is transmitted, and when this is confirmed, the other party performs channel switching, so that the original state “communication using one channel CH1 and the other channel CH2” is restored.

  According to this method, in order to perform wireless communication between the switching terminals 1b and 1c, two switching terminals need to transmit on the same frequency channel. It is essential that both 1b and 1c use the frequency channel CH1.

  However, this means that radio communication signals from terminals belonging to the group 4b using the frequency channel CH2 cannot be received during this period. Communication using the frequency channel CH2 cannot be performed from the channel switching condition detection time t1 (or t3) on one side to the time t2 (or t4) on channel switching signal reception and confirmation on the other side after confirmation. .

  Although this itself is an obstacle to always performing bidirectional communication, the degree of the obstacle can be reduced as follows. One of them is to perform switching in a short period of time.

  Another method uses the fact that downlink communication is ensured because the frequency channel CH1 is always alive. That is, when the aggregation device 2 cannot receive a response from the terminal even if the uplink communication is not ensured, the terminal transmits a data retransmission request using the downlink communication for which the constant communication is ensured. Loss of transmitted data can be prevented.

  As described above, according to this embodiment, one of the switching terminals 1b and 1c always uses the frequency channel CH1. That is, either the switching terminal 1b or 1c can surely receive the wireless communication signal transmitted by the terminal belonging to the group 4a.

  As a result, for example, when data is transmitted from the aggregation device 2 to the terminal 1e by multi-hop communication in the downlink direction, it is possible to avoid loss of wireless communication signals due to the switching terminal 1b or 1c switching the frequency channel. Is possible. That is, it is possible to preferentially control the data communication direction.

  Note that, by switching the switching order of the frequency channels of the switching terminals 1b and 1c and the transmission direction of the channel switching signal, one of the switching terminals 1b and 1c always uses the frequency channel CH2 and belongs to the group 4b. It is also possible to control so that either one of the switching terminals 1b or 1c can receive a wireless communication signal from the terminal.

  In this case, since the frequency channel CH2 is always alive, uplink communication is ensured, so that the aggregation device 2 can receive communication from the terminal 1 without loss. However, since downlink communication is not always ensured, if there is no response from the terminal to the command from the aggregation device 2, it is necessary to give the command from the aggregation device 2 again.

  The frequency channel switching method in FIG. 7 in the switching terminal will be described with reference to the flowchart of FIG. The flowchart shows the movement of the switching terminal 1b on the left side and the movement of the switching terminal 1c on the right side. It is assumed that the initial state of the flowchart is the same as in FIG. 7 and that the switching terminal 1b first detects the switching condition.

  In FIG. 8, the switching terminal 1b first detects a condition for switching the frequency channel in step S70. The condition for switching at this time may be, for example, that the frequency channel is switched when a preset time using a timer is reached.

  Next, switching terminal 1b changes the frequency channel from channel CH2 to 101 in step S71. Thereafter, in step S72, the switching terminal 1b transmits the channel switching signal 3a. Thereafter, the switching terminal 1b does not perform an operation related to switching until an instruction is given. Here, the instruction is reception of the channel switching signal 3b from the switching terminal 1c.

  On the other hand, the switching terminal 1c does not switch itself until it receives the channel switching signal 3a from the switching terminal 1b. In step S73, the switching terminal 1c confirms reception of the channel switching signal 3a and determines that the received signal is a channel switching instruction addressed to the own station. In step S74, when the channel switching signal is addressed to the own station, the switching terminal 1c changes the frequency channel from the channel CH1 to the channel CH2.

  Next, in step S75, the switching terminal 1c first stands by until a condition for switching the frequency channel is detected, and when detected, the switching terminal 1c changes the frequency channel from the channel CH2 to the channel CH1 in step S76. The condition for switching at this time may be, for example, that the frequency channel is switched when a preset time using a timer is reached.

  In step S77, after the channel switching, the switching terminal 1c transmits a channel switching signal 3b. Thereafter, the switching terminal 1c does not participate in channel switching until it receives the channel switching signal 3a again.

  Subsequently, the switching terminal 1b determines whether the channel switching signal 3b received in step S78 is a channel switching instruction addressed to the own station, and if it is a channel switching signal addressed to the own station in step S79, the switching terminal 1b. Changes the frequency channel from channel CH1 to 102.

  The subsequent operation in the switching terminal 1b is a repetition from step S70 to step S72. The switching terminal also repeatedly executes the procedure from step S73 to step S77.

  As described above, in the present embodiment, the wireless communication device 10 has a function of switching frequency channels, and by suppressing the interference of wireless communication signals by grouping a plurality of terminals by the frequency channel, the wireless communication device 10 belongs to different frequency channel groups. What is a terminal? A terminal that switches frequency channels has the function of relaying data, which can suppress interference of wireless communication signals, improve the effective communication speed of wireless communication networks, and improve communication reliability. It is. In addition, it is possible to efficiently transmit data to the terminals in the group using the same frequency channel by performing multicast communication.

  Next, a second embodiment for carrying out the present invention will be described in detail with reference to the drawings as appropriate.

  In the present embodiment, the channel switching between the switching terminals 1b and 1c is performed while the frequency channel switching condition detection is performed only in one switching terminal 1b. In the first embodiment described above, one channel is always communicable, while the other channel has a blank period during which communication is not possible. In the present embodiment, it is possible to make the communication speeds both average by allocating the blank periods evenly to the two channels, instead of concentrating them on one channel.

  The frequency channel switching process in the switching terminals 1b and 1c in this case will be described with reference to FIG. However, in the initial state, it is assumed that the switching terminal 1b executes the communication 102e using the channel CH2, and the switching terminal 1c executes the communication 102g using the channel CH1.

  First, the switching terminal 1b detects switching condition detection 201e for switching channels, and changes the frequency channel of the switching terminal 1b from communication 102e using channel CH2 to communication 101f using channel CH1 at time t1. However, the channel switching condition may be a condition that the channel is switched at a predetermined time using a timer, for example.

  After changing to channel CH1, switching terminal 1b transmits channel switching signal 3c to switching terminal 1c. When the switching terminal 1c receives the channel switching signal 3c and determines that the channel switching signal is an instruction addressed to the own station, the switching terminal 1c changes the communication 101g using the channel CH1 to the communication 102g using the channel CH2 at time t2.

  Next, switching terminal 1b detects switching condition detection 201f for switching the channel again, and changes the frequency channel of switching terminal 1b from communication 102f using channel CH1 to communication 102f using channel CH2 at time t3. . After changing to channel CH2, switching terminal 1b transmits channel switching signal 3d to switching terminal 1c. When the switching terminal 1c receives the channel switching signal 3d and determines that the channel switching signal is an instruction addressed to the own station, the switching terminal 1c changes from the communication 102g using the channel CH2 to the communication 101h using the channel CH1 at time t4.

  The switching process of each switching terminal in the second embodiment is as described above. As is clear from this figure, the preceding switching is executed only on one of the switching terminals (here, 1b), and the other switching is performed. The terminal (here 1c) only receives and follows the channel switching signal in a dependent manner. In order to realize the master-slave relationship, the configuration (channel switching control unit 12, channel switching condition detecting unit 13, channel switching signal determining unit 16, channel switching signal generating unit 17 of the wireless communication device 10 of FIG. The functions are as follows.

  First, in the switching terminal 1b that performs the preceding switching, the switching is performed based on its own judgment, and the result (channel switching signal) is only transmitted to the other party, so the channel switching signal determination unit 16 is not used. The switching terminal 1c that only receives and follows the channel switching signal dependently only receives and switches the channel switching signal, and therefore does not use the channel switching condition detection unit 13 and the channel switching signal generation unit 17. Since the cooperative operation of each part in FIG. 1 when both are configured in this way can be easily understood from the above description, detailed description thereof will be omitted here.

  When the above is performed, the channel switching signals 3c and 3d need to be transmitted in the same frequency channel. Therefore, during the channel switching time 300, the switching terminals 1b and 1c are either the frequency channel CH1 or 102. Wireless communication signals cannot be received from terminals belonging to the group using the other frequency channel. In the present embodiment, the period (communication blank period) during which this wireless communication signal cannot be received is implemented for the purpose of fairing the terminals of both groups.

  That is, when the switching terminal 1b in FIG. 9 switches from channel CH2 to channel CH1 and the switching terminal 1c switches from channel CH1 to channel CH2, a blank period 301 (period from t1 to t2) is generated on the channel CH2 side. When the switching terminal 1b switches from the channel CH1 to the channel CH2 and the switching terminal 1c switches from the channel CH2 to the channel CH1, a blank period 302 (period from t3 to t4) occurs on the channel CH1 side. Can be made generally uniform.

  In the case of FIG. 9, the method by which the switching terminal switches the frequency channel will be described using the flowchart of FIG.

  The switching terminal 1b first detects a condition for switching the frequency channel in step S80. The condition for switching at this time may be, for example, that the frequency channel is switched when a preset time using a timer is reached. Next, switching terminal 1b changes the frequency channel from channel CH2 to channel CH1 in step S81. Thereafter, the switching terminal 1b transmits a channel switching signal 3c to the switching terminal 1c in step S82.

  The switching terminal 1c that has received the channel switching signal 3c determines whether or not the channel switching signal 3c received in step S83 is a channel switching instruction addressed to itself. If it is a channel switching signal addressed to the own station, the switching terminal 1c changes the frequency channel from channel CH1 to channel CH2 in step S84.

  Next, the switching terminal 1b again detects the condition for switching the frequency channel in step S80. In step S81, the switching terminal 1b changes the frequency channel from the channel CH1 to the channel CH2. Thereafter, the switching terminal 1b transmits a channel switching signal 3d to the switching terminal 1c in step S82.

  The switching terminal 1c that has received the channel switching signal 3d determines whether or not the channel switching signal 3d received in step S83 is a channel switching instruction addressed to itself. If it is a channel switching signal addressed to the own station, switching terminal 1c changes the frequency channel from channel CH2 to channel CH1 in step S84.

  In this way, the switching terminals 1b and 1c continue to perform this operation thereafter. In this embodiment, the channel switching signal 3 is always provided by the switching terminal 1b, and the switching terminal performs channel switching following each time the channel switching signal 3 is received.

  As described above, in the present embodiment, by changing the frequency channel switching method in the switching terminal, a period during which wireless communication signals of terminals belonging to a group that uses a frequency channel different from the frequency channel of the switching terminal cannot be received (communication blank period) ) In a fair manner, and the effective communication speed in the uplink or downlink direction of the communication can be both averaged.

  Next, a third embodiment for carrying out the present invention will be described in detail with reference to the drawings as appropriate.

  In this embodiment, a channel switching signal and a channel switching response signal are transmitted and received in order to switch frequency channels between switching terminals. The channel switching response signal is used to confirm whether the frequency channel switching is properly performed in the partner switching terminal, and has an effect of making the frequency channel switching process more reliable. When the channel switching response signal is not received, the frequency channel switching process can be appropriately performed by transmitting the channel switching signal again.

  The frequency channel switching process in the switching terminals 1b and 1c will be described with reference to FIG. However, the communication channel switching in FIG. 11 is applied to the embodiment of FIG. In the initial state, it is assumed that the switching terminal 1b is executing the communication 102h using the channel CH2, and the switching terminal 1c is executing the communication 101j using the channel CH1.

  First, switching terminal 1b detects switching condition detection 201g for switching channels, and changes the frequency channel of switching terminal 1b from communication 102h using channel CH2 to communication 101i using channel CH1 at time t1. However, the channel switching condition may be a condition that the channel is switched at a predetermined time using a timer, for example.

  After switching to channel CH1, switching terminal 1b transmits channel switching signal 3e to switching terminal 1c. When the switching terminal 1c receives the channel switching signal 3e and determines that the channel switching signal is an instruction addressed to the own station, the switching terminal 1c transmits a channel switching response signal 6a to the switching terminal 1b. Further, the switching terminal 1c continues to change from the communication 101j using the channel CH1 to the communication 102j using the channel CH2 at time t2. In addition, the switching terminal 1b which received the channel switching response signal 6a confirms that the switching terminal 1c is operating normally with the reception. If the channel switching response signal 6a is not received within a predetermined period, the channel switching signal 3e is transmitted again to prompt the operation of the switching terminal 1c.

  Subsequently, the switching terminal 1c detects the switching condition detection 201h for switching the channel, and changes the frequency channel of the switching terminal 1c from the communication 102j using the channel CH2 to the communication 101k using the channel CH1 at time t3. .

  After changing to the channel CH1, the switching terminal 1c transmits a channel switching signal 3f to the switching terminal 1b. When the switching terminal 1b receives the channel switching signal 3f and determines that the channel switching signal is an instruction addressed to the own station, the switching terminal 1b transmits a channel switching response signal 6b to the switching terminal 1c. Further, switching terminal 1b continues to change from communication 101i using channel CH1 to communication 102i using channel CH2 at time t4. In addition, the switching terminal 1c which received the channel switching response signal 6b confirms that the switching terminal 1b is operating normally with the reception. If the channel switching response signal 6b is not received within the predetermined period, the channel switching signal 3f is transmitted again to prompt the operation of the switching terminal 1b.

  As is apparent from the comparison of FIG. 11 with FIG. 7, the third embodiment is a system in which a channel switching response signal is added and transmitted mutually in the first embodiment. Accordingly, all the configurations related to channel switching (the functions of the channel switching control unit 12, the channel switching condition detection unit 13, the channel switching signal determination unit 16, and the channel switching signal generation unit 17) of the wireless communication device 10 of FIG. To do.

  In addition, the following functions are added to the channel switching control unit 12. First, when the self is in a position to transmit the channel switching signal 3, the channel switching signal control unit 12 starts time counting from this transmission time, and the channel switching response signal 6 is sent to the channel switching signal determination unit 16 within a predetermined time. If not obtained, the channel switching signal generator 17 is driven to transmit the channel switching signal 3 again. This operation may be continuously executed until the channel switching response signal 6 is obtained in the channel switching signal determination unit 16. When the channel switching signal control unit 12 receives the channel switching signal 3, the channel switching signal control unit 12 drives the channel switching signal generation unit 17, transmits the channel switching response signal 6, and executes its own channel switching. Good.

  Next, a method for switching frequency channels by the switching terminal will be described with reference to FIG. However, this third embodiment basically inherits the technique of the first embodiment. FIG. 12 is different from FIG. 8 because some operations have been added to the items already described in FIG. 7 and FIG. 8 and the operation corresponding to FIG. 7 has already been described in FIG. Only the point will be described.

  In FIG. 12, when the switching terminal 1c that has received the channel switching signal 3e determines that the channel switching signal 3e is received in step S73, the switching terminal 1c executes a new step S90 prior to the channel switching in step S74. In step S90, a channel switching response signal 6a for notifying the switching terminal 1b that the channel switching signal 3e has been received is transmitted.

  On the other hand, step S91 and step S92 are added to the switching terminal 1b on the side that has transmitted the channel switching signal 3e. In step S91, the time from when the channel switching signal 3e is transmitted until the channel switching response signal 6a is received is monitored. If there is reception within the time, the next channel switching signal 3f is received. The switching operation as the switching terminal 1b is not executed. If there is no reception within the time, the channel switching signal 3e is determined to be retransmitted in step S92, and the channel switching signal 3e is retransmitted from step S72.

  The same process is executed when the situation is reversed. That is, the switching terminal 1b receives the channel switching signal 3f. In FIG. 12, when the switching terminal 1b that has received the channel switching signal 3f determines that the channel switching signal 3f is received in step S78, the switching terminal 1b executes a new step S100 prior to the channel switching in step S79. In step S100, a channel switching response signal 6b for notifying the switching terminal 1c that the channel switching signal 3f has been received is transmitted.

  On the other hand, in the switching terminal 1c on the side that has transmitted the channel switching signal 3f, steps S101 and S102 are added. In step S101, the time from when the channel switching signal 3f is transmitted until the channel switching response signal 6b is received is monitored. If there is reception within the time, the next channel switching signal 3e is received. The switching operation as the switching terminal 1c is not executed. If there is no reception within the time, the channel switching signal 3f is determined to be retransmitted in step S102, and the channel switching signal 3f is retransmitted from step S76.

  As described above, in the present embodiment, by changing the frequency channel switching method in the switching terminal and transmitting / receiving the channel switching signal and the channel switching response signal, it is determined whether the frequency switching is appropriately performed in the partner switching terminal. This makes it possible to confirm the frequency channel switching process, and has the effect of making the frequency channel switching process more reliable.

  Next, a fourth embodiment for carrying out the present invention will be described in detail with reference to the drawings as appropriate.

  In the present embodiment, three frequency channel switching terminals are used. When there are two switching terminals, the frequency channels of the two switching terminals must be temporarily the same during the channel switching time, and wireless communication signals from terminals belonging to groups using other frequency channels are transmitted. Improve the problem of not being able to receive.

  As shown in FIG. 13, three switching terminals 1f, 1g, and 1h are provided at the boundary between groups 4a and 4b. The channel switching signal 3 is transmitted and received between the switching terminals 1f, 1g, and 1h.

  The frequency channel switching process in the switching terminals 1f, 1g, and 1h will be described with reference to FIG. However, in the initial state, the switching terminal 1f executes the communication 102k using the channel CH2, the switching terminal 1g executes the communication 101n using the channel CH1, and the switching terminal 1h uses the channel CH2. It is assumed that the communication 102n is executed. As a result, one communication using the channel CH1 and two communication using the channel CH2 are performed.

  In such a situation, channel switching is started from the switching terminal 1f, which is one of the switching terminals using the channel CH2 in which two communications are being performed, and the channel CH1 in which one communication has been performed after the switching is performed. The switching terminal 1g to be used is switched, and the switching terminal 1h that is left last is switched in order.

  First, the switching terminal 1f that starts first detects the switching condition detection 201i for switching the channel, and at time t1, the frequency channel of the switching terminal 1f is changed from the communication 102k using the channel CH2 to the communication 101m using the channel CH1. Change to

  After switching to the channel CH1, the switching terminal 1f transmits a channel switching signal 3g to the switching terminal 1g. When the switching terminal 1g receives the channel switching signal 3g and determines that the channel switching signal is an instruction addressed to the own station, the switching terminal 1g changes the communication 101n by the channel CH1 to the communication 102m by the channel CH2 at time t2.

  Moreover, the switching terminal 1g transmits the channel switching signal 3h to the switching terminal 1h after changing to channel CH2. When the switching terminal 1h receives the channel switching signal 3h and determines that the channel switching signal is an instruction addressed to the own station, the switching terminal 1h changes from the communication 102n using the channel CH2 to the communication 101o using the channel CH1 at time t3.

  As a result, it is understood that the communication is always secured by the three switching terminals 1f, 1g, and 1h in the channel 1 and the channel 2 from before the time t1 to after the time t3 after the last switching. That is, until the last switching time t3, the channel CH2 is secured by the switching terminal 1h, and the channel CH1 is always secured by switching the switching terminals 1f and 1g with overlapping periods. .

  The next switching may be performed sequentially in the order of the switching terminals 1f, 1g, and 1h in the same flow as described above. In this case, three sets of channels 1 and 2 are consistently provided. The continuous switching is ensured by the switching terminals 1f, 1g, and 1h.

  As is clear by comparing FIG. 14 with FIG. 9, the fourth embodiment is a modification of the second embodiment. That is, the switching terminals 1f and 1h in FIG. 14 move in exactly the same way as the switching terminals 1b and 1c in FIG. Accordingly, the switching terminals 1f and 1h may have the same circuit configuration as in FIG. 1 as the switching terminals 1b and 1c in FIG. On the other hand, the switching terminal 1g of FIG. 14 is configured as follows.

  Since the switching terminal 1g has a function of receiving the channel switching signal 3g, switching its own channel, and transmitting the channel switching signal 3h, the switching terminal 1g does not use the channel switching condition detection unit 13 of FIG. Then, the channel switching control unit 12 drives the channel switching signal generation unit 17 and sends the channel switching signal 3h to the switching terminal 1h when the channel switching signal determination unit 16 confirms the channel switching signal 3g. . In addition, the wireless communication unit 11 is used to switch its own channel.

  Next, a method in which the switching terminal switches the frequency channel will be described with reference to FIG. In step S110, the switching terminal 1f first detects a condition for switching the frequency channel. Next, the switching terminal 1f changes the frequency channel from channel CH2 to 101 in step S111. Thereafter, the switching terminal 1f transmits a channel switching signal 3g in step S112.

  Next, the operation of the switching terminal 1g will be described. In step S113, the switching terminal 1g first determines the channel switching signal 3g received from the switching terminal 1f, and detects that this is directed to itself. Next, switching terminal 1g changes the frequency channel from channel CH1 to channel 102 in step S114. Thereafter, the switching terminal 1g transmits the channel switching signal 3h toward the switching terminal 1h in step S115.

  Next, the operation of the switching terminal 1h will be described. In step S116, the switching terminal 1h first determines the channel switching signal 3h received from the switching terminal 1g, and detects that it is directed to itself. Next, switching terminal 1h changes the frequency channel from channel CH2 to 101 in step S117.

  As described above, in the present embodiment, three switching terminals are used, and at least one of the three switching terminals always uses the channel CH1 or 102 during the channel switching time. 4b, at least one of the three switching terminals can always receive the wireless communication signal transmitted from the terminal belonging to 4b, and the wireless communication network can be made highly reliable.

  Next, a fifth embodiment for carrying out the present invention will be described in detail with reference to the drawings as appropriate.

  In this embodiment, the frequency channel is configured to use three channels. When the number of terminals is large, the number of terminals per channel increases when the number of channels is only two, and radio communication signals easily interfere with each other in the group using the same frequency channel, thereby reducing reliability. . Thus, by using three channels, the number of terminals per channel is reduced and interference of radio communication signals of terminals within the group is suppressed. When the number of terminals is larger, the number of channels is not limited to three, and four or more channels may be used.

  A configuration when three frequency channels are used will be described with reference to FIG. Assume that the aggregation device 2, the terminal 1a, and the switching terminals 1b and 1c belong to the group 4a that uses the first frequency channel CH1. The switching terminals 1b, 1c, 1i, 1j, and terminals 1d, 1e are assumed to belong to the group 4b that uses the second frequency channel CH2. The switching terminals 1i and 1j and the terminal 1k belong to the group 4c that uses the third frequency channel CH3.

  Between the switching terminals 1b and 1c located at the boundary between the group 4a and the group 4b, channel switching signals 3a and 3b are transmitted and received, and the frequency channel is switched between the channel CH1 and the channel CH2. The method for switching channels may be the method already shown in FIGS. Similarly, between the switching terminals 1i and 1j located at the boundary between the group 4b and the group 4c, channel switching signals 3i and 3j are transmitted and received, and the frequency channel is switched between the channel CH2 and the channel CH3. Similarly, the method for switching channels may be the method shown in FIGS.

  As described above, in this embodiment, the frequency channel is configured to use three channels, the number of terminals per channel is reduced, and interference of radio communication signals of terminals within the group is suppressed. As a result, the reliability of the wireless communication network is improved.

  In the first to fifth embodiments described above, the unit-type watt-hour meter 1 has been described as including the power amount measuring unit 30, the switch 40, and the wireless communication device 10, but the power amount The measurement unit 30 and the switch 40 may be independent devices and the wireless communication device 10 may be externally attached. In addition, the power amount measurement unit 30 or the switch 40 may be configured to incorporate the wireless communication device 10.

  According to the present invention, various meter readings can be easily realized, so that it can be applied to water supply and gas meter reading other than power meter reading, and can be widely applied not only to meter reading but also to wireless communication systems.

1: Unit-type energy meter
1a, 1d, 1e, 1k: Terminals 1b, 1c, 1f, 1g, 1h, 1i, 1j: Switching terminal 2: Aggregation device 3: Channel switching signal 4: Group 5: Core network 6a, 6b: Channel switching response signal 10 : Wireless communication device 11: wireless communication unit 12: channel switching control unit 13: channel switching condition detection unit 14: storage unit 15: communication control unit 16: channel switching signal determination unit 17: channel switching signal generation unit 18: input / output interface Unit 19: Power supply unit 20: Antenna 30: Electric energy measuring unit 40: Switch 50: Core network interface CH1-CH5: Frequency channels 201a, 201b, 201c, 201d: Channel switching condition detection 201e, 201g, 201h: Channel switching condition Detection 300, 301: Channel switching time

Claims (7)

Wireless communication between a first group formed by a plurality of wireless communication devices using a first frequency channel and a second group formed by a plurality of wireless communication devices using a second frequency channel A wireless communication system for performing
At least two wireless communication apparatuses can switch between the first frequency channel and the second frequency channel, and when the channel switching condition is detected, switch the frequency channel used by themselves, and then send a channel switching signal. A function of transmitting, and a function of determining that the received channel switching signal is a signal addressed to the own station and switching control of the frequency channel used by itself, wherein one of the wireless communication devices controls the first frequency channel A radio communication system characterized in that when used, the other radio communication apparatus uses the second frequency channel. The wireless communication system according to claim 1 , wherein
When it is determined that the received channel switching signal is an instruction addressed to its own station, a channel switching response signal is transmitted as a response indicating that the channel switching signal has been received, and switching control of the frequency channel used by itself is performed. A wireless communication system characterized by having the function of: The wireless communication system according to claim 2 , wherein
A wireless communication system having a function of performing retransmission of the channel switching signal when the channel switching response signal is not received within a predetermined time from transmission of the channel switching signal. Wireless communication between a first group formed by a plurality of wireless communication devices using a first frequency channel and a second group formed by a plurality of wireless communication devices using a second frequency channel A wireless communication system for performing
At least two wireless communication devices can switch between the first frequency channel and the second frequency channel, and the first wireless communication device switches the frequency channel used by itself when it detects a channel switching condition. After the control, the second wireless communication apparatus has a function of transmitting a channel switching signal, and the second wireless communication apparatus determines that the received channel switching signal is a signal addressed to the own station and performs switching control of the frequency channel used by itself. A wireless communication system having a function, wherein when one wireless communication apparatus uses the first frequency channel, the other wireless communication apparatus uses the second frequency channel. The wireless communication system according to claim 4 , wherein
Two or more second wireless communication devices are provided, and each second wireless communication device determines the frequency channel used by itself when it determines that the received channel switching signal is an instruction addressed to itself. A wireless communication system comprising a function of performing switching control and transmitting a channel switching signal toward another second wireless communication apparatus. A first group formed by a plurality of wireless communication devices using a first frequency channel, a second group formed by a plurality of wireless communication devices using a second frequency channel, and a third frequency A wireless communication system for performing wireless communication with a third group formed by a plurality of wireless communication devices using a channel,
At least two first wireless communication devices are provided for performing wireless communication between the first group and the second group, and the first wireless communication device includes the first frequency. The channel and the second frequency channel can be used by switching, and when the channel switching condition is detected, the function of transmitting the channel switching signal after the switching control of the frequency channel used by itself and the received channel switching signal are A function of determining that the signal is a destination signal and switching control of a frequency channel used by itself; when one wireless communication device uses the first frequency channel, the other wireless communication device Two frequency channels and at least two second wireless communication devices for performing wireless communication between the second group and the third group. And the second wireless communication apparatus can switch between the second frequency channel and the third frequency channel, and switches the frequency channel used by the second wireless communication device when detecting the channel switching condition. A function of transmitting a channel switching signal, and a function of determining that the received channel switching signal is a signal addressed to the own station and switching control of a frequency channel used by the own station, A wireless communication system, wherein when the second frequency channel is used, the other wireless communication device uses the third frequency channel. In the radio | wireless communications system in any one of Claim 1 to 6 ,
A wireless communication system for meter reading, wherein the wireless communication device is installed in a meter reading device of a meter reading target facility and wirelessly communicates meter reading data.

Images