JP5919561B2 - Metering communication terminal station and metering communication system - Google Patents

Description

  The present invention relates to a meter reading communication terminal station and a meter reading communication system.

  Conventionally, a meter reading communication terminal station is provided in a customer's facility that uses a supply medium supplied from a supplier, and a meter reading communication system is configured. The metering communication terminal station wirelessly transmits the meter reading information obtained by measuring the amount of supply medium used to the master station installed by the supplier, the handy terminal carried by the meter reader, etc. The usage amount is notified to the supplier (for example, see Japanese Patent Publication No. 2011-250301). Note that the supply medium includes electric power, water, gas, and the like.

  The metering communication terminal station can use a plurality of communication channels, selects one of the plurality of communication channels as a use channel, and performs communication using the use channel. A communication channel with a low channel usage rate is selected from the plurality of communication channels as the usage channel. The channel usage rate is a rate of time during which a signal is generated in the usage channel within a certain time, and the metering communication terminal station periodically derives the channel usage rate. Then, when the channel usage rate of the usage channel becomes equal to or higher than the upper limit usage rate, the metering communication terminal station changes the usage channel.

  For example, if the channel usage rate of the currently used channel is 40% or more of the upper limit usage rate, the meter reading communication terminal station changes the usage channel to another communication channel. As shown in FIG. 8A, it is assumed that the metering communication terminal station detects a signal generation time T11 every 25 msec in the use channel. In this case, T11 = 11 msec, and the channel usage rate = (11 msec / 25 msec) × 100 = 44%. Therefore, since the channel usage rate is 44%, the metering communication terminal station changes the use channel to another communication channel. When the channel usage rate of the usage channel is less than 40%, the metering communication terminal station continues to use the current usage channel.

  Further, the metering communication terminal station performs carrier sense in order to detect whether or not the use channel is idle before transmitting the packet. The meter-reading communication terminal starts packet transmission using the utilization channel after detecting that the utilization channel is empty by carrier sense.

  Specifically, the metering communication terminal station that performs carrier sense determines that the use channel is idle if no signal is generated in the use channel for 5 msec. The metering communication terminal station repeats this carrier sense every 5 msec when it cannot detect that the use channel is empty.

  As shown in FIG. 8B, it is assumed that a short-time signal such as an interference wave is generated in the use channel every 5 msec, which is the carrier sense execution cycle. The communication terminal station for meter reading detects the signal generation time T12 every 5 msec. In this case, T12 = 0.75 msec, and channel usage rate = (0.75 msec / 5 msec) × 100 = 15%. Accordingly, since the channel usage rate of the currently used channel is less than the upper limit usage rate of 40%, the metering communication terminal station continues to use without changing the current channel.

  However, since a short-time signal is generated in the use channel every 5 msec, which is the carrier sense execution period, the metering communication terminal station does not determine that the use channel is idle due to the carrier sense. Accordingly, since the metering communication terminal station cannot continue to detect that the channel being used is not available at the time of carrier sense, it cannot transmit a packet and a communication failure may occur.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a metering communication terminal station that can suppress communication failure by changing the channel even when a short-time signal is generated in the channel for each carrier sense execution period. It is to provide a communication system.

  The communication terminal station for meter reading according to the present invention is a communication terminal station for meter reading that transmits meter reading information representing the usage amount of a supply medium supplied from a supplier, and uses any one of a plurality of communication channels. A communication unit that selects as a channel and performs communication using the usage channel, and a carrier detection unit that performs carrier sense on the usage channel and repeats the carrier sense at a predetermined period when the usage channel is not idle. A derivation unit for deriving a ratio of a sum of signal generation times during which signals are generated in the use channel with respect to a certain time as a channel usage rate, and the communication unit includes the carrier sense of the carrier detection unit The transmission of the meter reading information is started when it is detected that the usage channel is in an empty state, and the channel usage of the usage channel is started. If the channel usage rate of the usage channel is less than the maximum usage rate, the usage channel is continuously used without being changed, and the derivation unit If the signal generation time is less than the minimum time obtained by multiplying the predetermined period by the upper limit usage rate when the carrier sense is continuously performed for the predetermined time, the signal generation time Is replaced with the minimum time to derive the channel usage rate.

  In the present invention, a usage rate storage unit that stores the channel usage rate of the usage channel is provided, and the derivation unit includes a plurality of communication channels each corresponding to the plurality of communication channels including the communication channel selected as the usage channel. A channel usage rate is derived, the usage rate storage unit stores the plurality of channel usage rates corresponding to the plurality of communication channels, and the communication unit determines that the channel usage rate of the usage channel is the upper limit usage. When the rate is equal to or higher than the rate, it is preferable to determine the change destination of the use channel based on the plurality of channel usage rates of the plurality of communication channels stored in the usage rate storage unit.

  In this invention, when the channel usage rate of the usage channel is greater than or equal to the upper limit usage rate, the communication unit is configured to correspond to the plurality of communication channels stored in the usage rate storage unit. Based on the usage rate, it is preferable that a communication channel corresponding to the lowest channel usage rate among the plurality of channel usage rates is the change destination of the usage channel.

  In this invention, when the channel usage rate of the usage channel is greater than or equal to the upper limit usage rate, the communication unit is configured to correspond to the plurality of communication channels stored in the usage rate storage unit. Based on the usage rate, it is preferable that a communication channel having the shortest sum of the signal generation times within a predetermined period of one day among the plurality of communication channels is a change destination of the use channel.

  In this invention, it is preferable that the communication unit does not use a communication channel corresponding to a channel usage rate that is equal to or higher than a first threshold among the plurality of communication channels as the usage channel.

  In the present invention, each of the plurality of communication channels includes a duration storage unit that stores a duration used as the usage channel, and the communication unit has a second threshold or less among the plurality of communication channels. It is preferable not to use a communication channel corresponding to a certain duration as the usage channel.

  In this invention, the communication unit sets the plurality of communication channels as a communication channel group, and in the communication channel group, the number of communication channels corresponding to a channel usage rate equal to or greater than a third threshold is equal to or greater than a predetermined number. The communication channel corresponding to the channel usage rate equal to or greater than the third threshold is deleted from the communication channel group, a new communication channel is added to the communication channel group, and the deleted communication channel and the It is preferable to notify the communication destination of the added communication channel information.

  The meter-reading communication system of the present invention includes a plurality of meter-reading communication terminal stations that transmit meter-reading information that indicates the amount of use of a supply medium supplied from a supplier, and each of the plurality of meter-reading communication terminal stations. Each of the plurality of meter-reading communication terminal stations selects one of the plurality of communication channels as a use channel, and performs communication using the use channel. Carrier sense is performed on the used channel, and when the used channel is not empty, a carrier detection unit that repeats the carrier sense at a predetermined period, and a signal is generated on the used channel for a certain period of time. A derivation unit that derives a ratio of the sum of signal generation times as a channel usage rate, and the communication unit uses the carrier channel according to the carrier sense of the carrier detection unit. The transmission of the meter-reading information is started when it is detected that the channel is free. When the channel usage rate of the usage channel is equal to or higher than the upper limit usage rate, the usage channel is changed, and the channel usage of the usage channel is changed. When the rate is less than the upper-limit usage rate, the usage channel is continuously used without being changed, and the derivation unit is configured to perform the signal generation time when the carrier sense is continuously performed for the certain period of time. If the predetermined period is less than the minimum time obtained by multiplying the upper limit usage rate, the signal generation time is replaced with the minimum time to derive the channel usage rate.

  In the present invention, each of the plurality of metering communication terminal stations includes a usage rate storage unit that stores the channel usage rate of the usage channel, and the derivation unit selects a communication channel selected as the usage channel. Deriving a plurality of channel usage rates respectively corresponding to the plurality of communication channels including, the usage rate storage unit stores the plurality of channel usage rates respectively corresponding to the plurality of communication channels, the communication unit, The plurality of channel usage rate information is transmitted to the master station, and the master station is configured to transmit the plurality of channel usage rate information based on the plurality of channel usage rate information transmitted from each of the plurality of meter-reading communication terminal stations. A communication channel that is not used as the use channel is determined in each of the metering communication terminal stations, and information on the communication channel that is not used as the use channel is determined in advance. It is preferable to transmit to each of the plurality of meter reading communication terminal station.

  As described above, in the present invention, even when a short-time signal is generated on the usage channel for each carrier sense execution cycle, the usage channel can be changed because the channel usage rate exceeds the upper limit usage rate. . Therefore, there is a high possibility that a signal can be transmitted without continuing the state in which it is not possible to detect that the use channel is idle at the time of carrier sense, and the occurrence of a communication failure can be suppressed. That is, even when a short-time signal is generated in the usage channel for each carrier sense execution cycle, there is an effect that the usage channel can be changed to suppress communication failure.

Preferred embodiments of the invention are described in further detail. Other features and advantages of the present invention will be better understood with reference to the following detailed description and accompanying drawings.
It is a block diagram which shows the system configuration | structure of embodiment. 2A to 2C are explanatory diagrams illustrating signals on the communication channel according to the embodiment. It is explanatory drawing which shows an example of the channel usage rate of embodiment. 4A to 4C are explanatory diagrams illustrating signal generation states of the communication channel according to the embodiment. It is a table figure which shows the channel status list of embodiment. 6A and 6B are explanatory diagrams illustrating changes in the communication channel group of the embodiment. 7A and 7B are explanatory diagrams illustrating changes in the communication channel group of the embodiment. 8A and 8B are explanatory diagrams showing signals on a conventional communication channel.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 shows a configuration of a meter reading communication system (remote meter reading communication system) using a plurality of meter reading communication terminal stations 1 (remote meter reading communication terminal stations).

  The metering communication terminal station 1 (first terminal station) is provided in a customer's facility that uses a supply medium supplied from a supplier, and a master station 2 (first station) installed by the supplier. 2 terminal stations), the handy terminal 3 (third terminal station) carried by the meter reader, etc., perform wireless communication with each other. And the communication terminal station 1 for meter-reading acquires the meter-reading information which measured the usage-amount of the supply medium from the meter-reading meter which is not shown in figure, and transmits to the master station 2 or the handy terminal 3 etc., thereby the supply medium in each consumer. The usage amount is notified to the supplier. This metering communication terminal station 1 is configured to directly communicate with the master station 2 or the handy terminal 3, or multi-hop between the master station 2 or the handy terminal 3 with another metering communication terminal station 1 as a relay station. Any configuration that performs communication may be used. Note that the supply medium includes electric power, water, gas, and the like.

  In general, the metering communication terminal station 1 is fixedly installed at each consumer, and therefore, once installed, it is difficult to move. Therefore, if a large number of communication terminals using the same frequency band are installed around the installation location of the own station, the metering communication terminal station 1 may cause a communication failure due to congestion, interference, or the like. . In particular, the frequency band used for wireless communication by the metering communication terminal station 1 is a 920 MHz band (that is, a frequency band centered on 920 MHz), and other HEMS (Home Electrical Management System) devices, sensor devices, tags, and the like. Communication terminals are also used for communication.

  Further, since the handy terminal 3 approaches the meter reading communication terminal station 1 to be metered when the meter reader performs meter reading work or maintenance work, the handy terminal 3 cannot grasp the surrounding communication environment in advance. Therefore, in this embodiment, the metering communication terminal station 1 is configured to grasp the surrounding communication environment in advance.

  Each metering communication terminal station 1 includes an antenna 1a, a communication unit 1b, a carrier detection unit 1c, a derivation unit 1d, a usage rate storage unit 1e, a duration storage unit 1f, and a calculation data storage unit 1g. Prepare.

  The communication unit 1b can use a plurality of communication channels, selects any one of the plurality of communication channels as a use channel, and performs wireless communication via the antenna 1a using the use channel. A communication channel with a low channel usage rate is selected from the plurality of communication channels as the usage channel. The channel usage rate of the communication channel indicates a ratio of the sum of signal generation times in which signals are generated in the communication channel with respect to a certain time, and is a time ratio in which signals are generated in the communication channel.

  The deriving unit 1d derives the channel usage rate of the used channel. And the communication part 1b changes a utilization channel, when the channel usage rate of a utilization channel is more than an upper limit utilization rate. Note that the presence / absence determination of a signal in the communication channel is performed by comparing the received power level of the communication channel with a threshold value, and if the received power level is equal to or higher than the threshold value, it is determined that a signal is generated in the communication channel.

  Further, the carrier detection unit 1c performs carrier sense in order to detect whether or not the use channel is idle before transmission of the packet by the communication unit 1b. The carrier detection unit 1c determines that the use channel is idle if no signal is generated in the use channel for 5 msec. The communication unit 1b starts packet transmission using the usage channel after detecting that the usage channel is empty by carrier sense. Further, when the carrier detection unit 1c cannot detect that the use channel is in an empty state, the carrier detection unit 1c repeats this carrier sense every 5 msec (predetermined period).

  Next, the operation of deriving the channel usage rate by the deriving unit 1d will be described.

  The deriving unit 1d derives the ratio of the sum of the signal generation times during which signals are generated in the communication channel with respect to a certain time as the channel usage rate every 24 hours. That is, the channel usage rate derived by the deriving unit 1d is a ratio of the sum of signal generation times to 24 hours. In FIG. 2A, the deriving unit 1d detects the signal generation time T1 every 25 msec in the use channel, and this state continues for 24 hours. In this case, T1 = 11 msec, and the channel usage rate = (11 msec / 25 msec) × 100 = 44%.

  The communication unit 1b changes the usage channel to another communication channel if the channel usage rate of the currently used channel is 40% or more. When the state of FIG. 2A continues for 24 hours, the channel usage rate becomes 44%, so the communication unit 1b changes the use channel to another communication channel. When the channel usage rate of the usage channel is less than 40%, the communication unit 1b continues to use the current usage channel.

  On the other hand, as shown in FIG. 2B, a short-time signal (for example, an interference wave) generated from the sensor device 4 (see FIG. 1) is generated in the use channel every 5 msec which is the carrier sense execution cycle. Suppose that The deriving unit 1d detects the signal generation time T2 every 5 msec, and this state continues for 24 hours. In this case, T2 = 0.75 msec, and channel usage rate = (0.75 msec / 5 msec) × 100 = 15%. Therefore, when the state of FIG. 2B continues for 24 hours, the communication unit 1b continues without changing the current usage channel because the channel usage rate of the currently used channel is less than the upper limit usage rate of 40%. Will be used.

  However, since a signal is generated in the use channel every 5 msec, which is the carrier sense execution cycle, the carrier detection unit 1c cannot detect that the use channel is in an empty state by carrier sense. Therefore, the communication unit 1b cannot transmit a packet, and a communication failure may occur.

  Therefore, in the derivation unit 1d of the present embodiment, when the carrier sensing is continuously performed for a certain time (24 hours in the present embodiment) in the carrier detection unit 1c, the signal generation time is less than the predetermined minimum time. If so, the channel generation rate is derived by replacing this signal generation time with the minimum time. This minimum time is a value obtained by multiplying the carrier sense period of 5 msec by the upper limit usage rate of 40%, and is set to the minimum time = 2 msec.

  The signal generation time T2 = 0.75 msec in FIG. 2B is less than the minimum time 2 msec. Therefore, as shown in FIG. 2C, the deriving unit 1d regards the signal generation time T2 as the signal generation time T2a = 2 msec, and derives the channel usage rate. In this case, T2a = 2 msec, and channel usage rate = (2 msec / 5 msec) × 100 = 40%. Therefore, when the state of FIG. 2C continues for 24 hours, the communication unit 1b changes the usage channel to another communication channel because the channel usage rate of the currently used channel is 40% or more. Can do.

  In the present embodiment, even when a short-time signal is generated in the usage channel for each carrier sense execution period, the channel usage rate is 40% or more, so that the usage channel can be changed. Accordingly, the communication unit 1b is more likely to be able to transmit a packet without continuing the state where it is not possible to detect that the use channel is idle at the time of carrier sense, and the occurrence of a communication failure can be suppressed.

  Next, when the communication unit 1b changes the usage channel to another communication channel, a communication failure may occur after the usage channel is changed if the channel usage rate of the communication channel to which the usage channel is changed is high. . Therefore, a usage channel changing operation capable of suppressing a communication failure after the usage channel is changed will be described.

  First, the communication unit 1b can use a plurality of communication channels CH1 to CH5. Then, the communication unit 1b selects one of the communication channels CH1 to CH5 as a usage channel, and performs wireless communication via the antenna 1a using this usage channel. Hereinafter, the communication unit 1b uses the communication channel CH1 as a usage channel, and changes the usage channel CH1 to other communication channels CH2 to CH5.

  Then, the deriving unit 1d derives the channel usage rate for each of the communication channels CH1 to CH5, and stores the channel usage rates of the communication channels CH1 to CH5 in the usage rate storage unit 1e.

  Since the communication unit 1b normally performs communication using the usage channel CH1, the derivation unit 1d derives the channel usage rate of the usage channel CH1 (the ratio of the sum of signal generation times with respect to 24 hours) as needed. Can be updated.

  However, the communication channels CH2 to CH5 are not set as usage channels and are not used for normal communication. Therefore, the deriving unit 1d temporarily switches the use channel to one of the communication channels CH2 to CH5 for a predetermined time of the day, and assigns it to the process of detecting each signal generation time of the communication channels CH2 to CH5. Then, the operation of detecting the signal generation times of the communication channels CH2 to CH5 is performed for about one month, and the channel usage rates of the communication channels CH2 to CH5 (the ratio of the sum of the signal generation times with respect to 24 hours) are derived. That is, the channel usage rates of the communication channels CH2 to CH5 are updated once a month.

  The deriving unit 1d stores information on the channel usage rates of the communication channels CH1 to CH5 in the usage rate storage unit 1e.

  Then, when the channel usage rate of the usage channel CH1 becomes equal to or higher than the upper limit usage rate of 40%, the communication unit 1b has a plurality of channel usage rates respectively corresponding to the communication channels CH1 to CH5 stored in the usage rate storage unit 1e. Based on the above, the change destination of the use channel is determined.

  A first example for determining the change destination of the use channel will be described with reference to FIG. First, it is assumed that the channel usage rates of the communication channels CH1 to CH5 are “40%”, “15%”, “0%”, “60%”, and “25%”, respectively, as shown in FIG. . In this case, the communication unit 1b sets the communication channel CH3 having the lowest channel usage rate among the communication channels CH2, CH3, and CH5 whose channel usage rate is less than the upper limit usage rate of 40% as the usage channel change destination. Therefore, since the channel usage rate of the communication channel that is the change destination of the use channel is low, it is possible to suppress communication failure after the change of the use channel.

  Next, a second example of determining the change destination of the use channel will be described with reference to FIGS. First, it is assumed that the channel usage rates of the communication channels CH1 to CH5 are “40%”, “15%”, “40%”, “60%”, and “25%”, respectively, as illustrated in FIG. 4A. . In this case, there are CH2 and CH5 as communication channels whose channel usage rate is less than the upper limit usage rate of 40%. Here, the time zone in which the hand reading terminal 3 uses the handy terminal 3 to perform meter reading work or maintenance work is generally a day time. Therefore, the communication unit 1b sets the communication channel with the shortest sum of signal generation times during the daytime of the day (within a predetermined period of the day) as the usage channel change destination.

  First, the deriving unit 1d stores data of the signal generation time used when deriving the channel usage rates of the communication channels CH1 to CH5 in the operation data storage unit 1g. The communication unit 1b refers to the data in the calculation data storage unit 1g and determines that a signal is generated in the communication channel CH2 during the daytime (see FIG. 4B). Further, the communication unit 1b refers to the data in the calculation data storage unit 1g, and determines that a signal is generated in the communication channel CH5 at night, but no signal is generated in the daytime time zone ( (See FIG. 4C). Thus, the communication unit 1b determines that the communication channel CH5 has a shorter sum of signal generation times in the daytime than the communication channel CH2, and sets the communication channel CH5 as a use channel.

  Therefore, the communication channel that is the change destination of the use channel has a low channel usage rate in a time zone in which the meter reader uses the handy terminal 3 to perform meter reading work or maintenance work. Thus, it is possible to suppress the occurrence of communication failure when the handy terminal 3 is used after changing the use channel. In addition, the communication part 1b should just set the predetermined period of 1 day which is a comparison range to arbitrary time zones according to a communication destination.

  Next, a third example for determining the change destination of the use channel will be described. First, the channel usage rates of the communication channels CH1 to CH5 are “40%”, “15%”, “0%”, “60%”, and “25%”, respectively, as in FIG. 3 of the first example. Assume a case. In this case, the communication unit 1b sets the communication channel CH3 having the lowest channel usage rate among the communication channels CH2, CH3, and CH5 whose channel usage rate is less than the upper limit usage rate of 40% as the usage channel change destination. Further, the communication unit 1b transmits the communication channels CH1 and CH4 (first use prohibited channel) having a channel usage rate of 40% (first threshold) or more for a predetermined period (first use prohibited period) thereafter. Not used as a usage channel. That is, a communication channel with a channel usage rate of 40% or higher is likely to have a channel usage rate of 40% or higher again even if the channel usage rate subsequently decreases. To do. The communication channels CH1 and CH4 can be used again as usage channels after the first use prohibition period has elapsed. The first use prohibition period is set to an arbitrary period such as one week or one month.

  Therefore, since the communication channel whose channel usage rate has increased becomes the first use-prohibited channel during the first use-prohibited period, it is prevented that a communication channel that is likely to cause a communication failure becomes a use channel. . Thus, it is possible to suppress communication failures after changing the use channel.

  Further, the duration storage unit 1f stores the durations in which each of the communication channels CH1 to CH5 is used as a usage channel. This duration is an average value (or a maximum value) of the time length per time used as a usage channel when each of the communication channels CH1 to CH5 is selected as a normal usage channel.

  And the communication part 1b also uses a communication channel (2nd use prohibition channel) whose duration is below a threshold value (2nd threshold value) as a use channel during the subsequent predetermined period (2nd use prohibition period). do not use. That is, the communication channel with a short duration used as the usage channel is set as the second use-prohibited channel because the communication environment is unstable. The second use-prohibited channel becomes usable again as a use channel after the second use-prohibited period has elapsed. The second use prohibition period is set to an arbitrary period such as one week or one month. A communication channel that has never been used as a usage channel may be excluded from the second use-prohibited channel.

  Therefore, the communication channel having a short duration becomes the second use-prohibited channel during the second use-prohibited period, so that a communication channel that is likely to cause a communication failure is prevented from being used. Thus, it is possible to suppress communication failures after changing the use channel.

  Next, a fourth example of determining the change destination of the usage channel will be described.

  First, the channel usage rates of the communication channels CH1 to CH5 are “40%”, “15%”, “0%”, “60%”, and “25%”, respectively, as in FIG. 3 of the first example. Assume a case. In this case, the communication unit 1b sets the communication channel CH3 having the lowest channel usage rate among the communication channels CH2, CH3, and CH5 whose channel usage rate is less than the upper limit usage rate of 40% as the usage channel change destination. And the communication part 1b produces the channel status list L1 (refer FIG. 5) as information of each channel usage rate of communication channel CH1-CH5, and memorize | stores it in the memory which is not illustrated inside. In the channel status list L1, the communication channel CH3 set as the use channel is represented by “◯”. In addition, communication channels CH2 and CH5 that are not used as current usage channels among communication channels having a channel usage rate of less than the upper limit usage rate of 40% are represented by “Δ”. Communication channels CH1 and CH4 whose channel usage rate is 40% or more of the upper limit usage rate are represented by “x”.

  Then, the communication unit 1b of each meter-reading communication terminal station 1 transmits the channel status list L1 to the master station 2. The master station 2 receives the channel status list L1 from each of the plurality of meter-reading communication terminal stations 1. That is, the master station 2 can grasp information on a plurality of channel usage rates corresponding to a plurality of communication channels for each of the plurality of meter reading communication terminal stations 1 under its control. Then, the master station 2 determines a third use-prohibited channel in each of the meter-reading communication terminal stations 1 based on the channel status list L1 of each of the subordinate meter-reading communication terminal stations 1. That is, the master station 2 considers the status of each communication channel of other meter-reading communication terminal stations 1 located around each meter-reading communication terminal station 1, and the third station in each meter-reading communication terminal station 1 Determine which channels are disabled.

  Then, the master station 2 transmits information on the third use-prohibited channel determined for each meter-reading communication terminal station 1 to each meter-reading communication terminal station 1. The communication unit 1b of each metering communication terminal station 1 does not use the third use-prohibited channel notified to the self-end station as a use channel during the subsequent predetermined period (third use-prohibited period). The third use-prohibited channel becomes usable again as a use channel after the third use-prohibited period has elapsed.

  Therefore, the third use-prohibited channel in each meter-reading communication terminal station 1 is determined in consideration of not only the own terminal station but also the status of other meter-reading communication terminal stations 1 in the surrounding area. Operation is based on the environment.

  Further, among the communication channels CH1 to CH5, when the number of communication channels having a channel usage rate of 40% or more increases, the communication channels that can be used as the use channel by the communication unit 1b may decrease, and the communication may be disabled. .

  For example, as shown in FIG. 6A, it is assumed that the channel usage rates of the communication channels CH1 to CH5 are “40%”, “15%”, “40%”, “60%”, and “25%”. In this case, of the five communication channels, the channel usage rate of the three communication channels is 40% or more. 6A, the channel usage rates of the communication channels CH1 to CH5 are “40%”, “45%”, “40%”, “60%”, “55%” as shown in FIG. 6B. Assuming that In this case, the channel usage rate becomes 40% or more in all the five communication channels, and communication is disabled.

  Therefore, the communication unit 1b sets a plurality of communication channels CH1 to CH5 as one communication channel group. When the number of communication channels having a channel usage rate of 40% (third threshold) or more in the communication channel group becomes equal to or greater than a predetermined value (for example, 3), the communication unit 1b 40% or more of communication channels are deleted from the communication channel group, and a new communication channel is added to the communication channel group.

  For example, as shown in FIG. 7A, it is assumed that the channel usage rates of the communication channels CH1 to CH5 are “40%”, “15%”, “40%”, “60%”, and “25%”. In this case, of the five communication channels, the channel usage rates of the three communication channels CH1, CH3, and CH4 are 40% or more. Therefore, the communication unit 1b deletes the communication channels CH1, CH3, and CH4 from the communication channel group as shown in FIG. 7B because the number of communication channels having a channel usage rate of 40% or more has become three or more. Further, the communication unit 1b adds new communication channels CH6, CH7, and CH8 to the communication channel group.

  Therefore, the communication unit 1b can maintain the number of communication channels having a channel usage rate of 40% or more in the communication channel group used by the terminal station for communication to two or less, thereby preventing a communication failure state. doing.

  Further, the communication unit 1b sends the information of the deleted communication channels CH1, CH3, and CH4 and the information of the added communication channels CH6, CH7, and CH8 to other metering communication terminal stations 1, the master station 2, and the communication destination. Send to Handy Terminal 3 Therefore, since the metering communication terminal station 1 notifies the communication destination in the system of the communication channel that can be currently used, communication is not hindered by deleting or adding the communication channel.

  As described above, the meter-reading communication terminal station 1 according to the present embodiment transmits meter-reading information representing the usage amount of the supply medium supplied from the supplier by the customer. The metering communication terminal station 1 selects one of a plurality of communication channels (for example, five communication channels CH1 to CH5) as a use channel, and performs communication using the use channel with the communication unit 1b. When the carrier sense is performed and the use channel is not empty, the carrier detection unit 1c that repeats the carrier sense at a predetermined period and the ratio of the sum of the signal generation times that the signal is generated in the use channel with respect to a certain time A deriving unit 1d for deriving the usage rate. The communication unit 1b starts transmission of meter-reading information when it detects that the usage channel is empty by carrier sense of the carrier detection unit 1c. When the channel usage rate of the usage channel is equal to or higher than the upper limit usage rate, If the channel is changed and the channel usage rate of the usage channel is less than the upper limit usage rate, the usage channel is continuously used without being changed. If the carrier generation is continuously performed for a certain time, the deriving unit 1d determines that the signal generation time is the minimum time if the signal generation time is less than the minimum time obtained by multiplying the predetermined period by the upper limit usage rate. Is used to derive the channel usage rate.

  Moreover, it is preferable that the meter-reading communication terminal station 1 of the present embodiment further includes a usage rate storage unit 1e for storing the channel usage rate of the usage channel. In this case, the deriving unit 1d derives a plurality of channel usage rates respectively corresponding to a plurality of communication channels including the communication channel selected as the usage channel. The usage rate storage unit 1e stores a plurality of channel usage rates respectively corresponding to a plurality of communication channels. When the channel usage rate of the usage channel is equal to or higher than the upper limit usage rate, the communication unit 1b determines the change destination of the usage channel based on the plurality of channel usage rates of the plurality of communication channels stored in the usage rate storage unit 1e. decide.

  Moreover, in the communication terminal station 1 for meter reading according to the present embodiment, the communication unit 1b is respectively connected to the plurality of communication channels stored in the usage rate storage unit 1e when the channel usage rate of the usage channel is equal to or higher than the upper limit usage rate. Based on the corresponding plurality of channel usage rates, it is preferable that the communication channel corresponding to the lowest channel usage rate among the plurality of channel usage rates is the change destination of the usage channel.

  Moreover, in the communication terminal station 1 for meter reading according to the present embodiment, the communication unit 1b is respectively connected to the plurality of communication channels stored in the usage rate storage unit 1e when the channel usage rate of the usage channel is equal to or higher than the upper limit usage rate. Based on the corresponding plurality of channel usage rates, it is preferable that the communication channel having the shortest sum of signal generation times within a predetermined period of one day among the plurality of communication channels is the change destination of the use channel.

  Further, in the communication terminal station 1 for meter reading according to the present embodiment, it is preferable that the communication unit 1b does not use a communication channel corresponding to a channel usage rate that is equal to or higher than the first threshold as a usage channel among a plurality of communication channels. .

  Moreover, it is preferable that the meter-reading communication terminal station 1 of the present embodiment further includes a duration storage unit 1f that stores a duration in which each of the plurality of communication channels is used as a use channel. In this case, the communication unit 1b does not use a communication channel corresponding to a duration that is equal to or less than the second threshold among the plurality of communication channels as a usage channel.

  Moreover, in the communication terminal station 1 for meter reading according to the present embodiment, the communication unit 1b sets a plurality of communication channels as a communication channel group, and communication corresponding to a channel usage rate that is equal to or greater than a third threshold in the communication channel group. When the number of channels is equal to or greater than the predetermined number, the communication channel corresponding to the channel usage rate equal to or greater than the third threshold is deleted from the communication channel group, and a new communication channel is added to the communication channel group, and the deleted communication channel It is preferable to notify the communication destination of information of the added communication channel.

  In addition, as described above, the meter-reading communication system of the present embodiment includes a plurality of meter-reading communication terminal stations 1 that transmit meter-reading information representing the amount of use of a supply medium supplied from a supplier by a consumer, A master station 2 that performs communication with each of the metering communication terminal stations 1. Each of the plurality of meter-reading communication terminal stations 1 selects one of a plurality of communication channels as a use channel, performs communication using the use channel, and performs a carrier sense on the use channel, Derivation for deriving, as a channel usage rate, a carrier detection unit 1c that repeats carrier sensing at a predetermined period and a ratio of the sum of signal generation times in which a signal is generated in the usage channel for a certain time when the usage channel is not empty. Part 1d. The communication unit 1b starts transmission of meter-reading information when it detects that the usage channel is empty by carrier sense of the carrier detection unit 1c. When the channel usage rate of the usage channel is equal to or higher than the upper limit usage rate, If the channel is changed and the channel usage rate of the usage channel is less than the upper limit usage rate, the usage channel is continuously used without being changed. If the carrier generation is continuously performed for a certain time, the deriving unit 1d determines that the signal generation time is the minimum time if the signal generation time is less than the minimum time obtained by multiplying the predetermined period by the upper limit usage rate. Is used to derive the channel usage rate.

  In the meter-reading communication system of the present embodiment, each of the plurality of meter-reading communication terminal stations 1 preferably further includes a usage rate storage unit 1e that stores the channel usage rate of the usage channel. In this case, the deriving unit 1d derives a plurality of channel usage rates respectively corresponding to a plurality of communication channels including the communication channel selected as the usage channel. The usage rate storage unit 1e stores a plurality of channel usage rates respectively corresponding to a plurality of communication channels. The communication unit 1 b transmits information on a plurality of channel usage rates to the master station 2. The master station 2 determines a communication channel that is not used as a use channel in each of the plurality of meter reading communication terminal stations 1 based on the information on the plurality of channel usage rates transmitted from each of the plurality of meter reading communication terminal stations 1. Then, information on communication channels that are not used as usage channels is transmitted to each of the plurality of meter-reading communication terminal stations 1.

  While the invention has been described in terms of several preferred embodiments, various modifications and variations can be made by those skilled in the art without departing from the true spirit and scope of the invention, ie, the claims.

Claims (9)

A communication terminal station for meter reading that transmits meter reading information indicating the amount of use of a supply medium supplied from a supplier in a consumer,
A communication unit that selects one of a plurality of communication channels as a use channel and performs communication using the use channel;
Carrier sensing is performed for the usage channel, and when the usage channel is not empty, a carrier detection unit that repeats the carrier sensing at a predetermined period;
A derivation unit for deriving, as a channel usage rate, a ratio of a sum of signal generation times in which signals are generated in the usage channel with respect to a certain time,
The communication unit is
When it is detected by the carrier sense of the carrier detection unit that the use channel is idle, transmission of the meter reading information is started,
When the channel usage rate of the usage channel is equal to or higher than the upper limit usage rate, the usage channel is changed,
If the channel usage rate of the usage channel is less than the upper limit usage rate, continue to use the usage channel without changing,
The derivation unit, when the carrier sense is continuously performed over the predetermined time, if the signal generation time is less than the minimum time obtained by multiplying the predetermined period by the upper limit usage rate, this signal The channel usage rate is derived by replacing the occurrence time with the minimum time. A usage rate storage unit for storing the channel usage rate of the usage channel;
The deriving unit derives a plurality of channel usage rates respectively corresponding to the plurality of communication channels including the communication channel selected as the usage channel;
The usage rate storage unit stores the plurality of channel usage rates corresponding to the plurality of communication channels, respectively.
The communication unit, when the channel usage rate of the usage channel is equal to or higher than the upper limit usage rate, based on the plurality of channel usage rates of each of the plurality of communication channels stored in the usage rate storage unit, The communication terminal station for meter reading according to claim 1, wherein a change destination of a use channel is determined.   When the channel usage rate of the usage channel is equal to or higher than the upper limit usage rate, the communication unit is based on the plurality of channel usage rates respectively corresponding to the plurality of communication channels stored in the usage rate storage unit. The metering communication terminal station according to claim 2, wherein a communication channel corresponding to the lowest channel usage rate among the plurality of channel usage rates is set as a change destination of the usage channel.   When the channel usage rate of the usage channel is equal to or higher than the upper limit usage rate, the communication unit is based on the plurality of channel usage rates respectively corresponding to the plurality of communication channels stored in the usage rate storage unit. The metering communication according to claim 2, wherein a communication channel having the shortest sum of the signal generation times within a predetermined period of one day among the plurality of communication channels is set as a change destination of the use channel. Terminal station.   3. The metering communication terminal station according to claim 2, wherein the communication unit does not use, as the usage channel, a communication channel corresponding to a channel usage rate that is equal to or higher than a first threshold among the plurality of communication channels. . A duration storage unit that stores a duration of each of the plurality of communication channels used as the usage channel;
The metering communication terminal station according to claim 5, wherein the communication unit does not use, as the utilization channel, a communication channel corresponding to a duration that is equal to or less than a second threshold among the plurality of communication channels.   The communication unit sets the plurality of communication channels as a communication channel group, and in the communication channel group, when the number of communication channels corresponding to a channel usage rate equal to or greater than a third threshold is equal to or greater than a predetermined number, The communication channel corresponding to the channel usage rate equal to or greater than the third threshold is deleted from the communication channel group, a new communication channel is added to the communication channel group, the deleted communication channel and the added communication channel 7. The metering communication terminal station according to claim 2, wherein the information is notified to a communication destination. A master station that performs communication between a plurality of meter reading communication terminal stations that transmit meter reading information representing the amount of use of a supply medium supplied from a supplier by a consumer and each of the plurality of meter reading communication terminal stations And
Each of the plurality of metering communication terminal stations selects any one of a plurality of communication channels as a use channel, performs a communication using the use channel, performs carrier sense for the use channel, When the use channel is not empty, a carrier detection unit that repeats the carrier sense at a predetermined period and a ratio of the sum of signal generation times in which the signal is generated in the use channel with respect to a certain time is derived as a channel use rate. And a derivation unit
The communication unit is
When it is detected by the carrier sense of the carrier detection unit that the use channel is idle, transmission of the meter reading information is started,
When the channel usage rate of the usage channel is equal to or higher than the upper limit usage rate, the usage channel is changed,
If the channel usage rate of the usage channel is less than the upper limit usage rate, continue to use the usage channel without changing,
The derivation unit, when the carrier sense is continuously performed over the predetermined time, if the signal generation time is less than the minimum time obtained by multiplying the predetermined period by the upper limit usage rate, this signal The meter reading communication system, wherein the channel usage rate is derived by replacing the generation time with the minimum time. Each of the plurality of metering communication terminal stations includes a usage rate storage unit that stores the channel usage rate of the usage channel,
The deriving unit derives a plurality of channel usage rates respectively corresponding to the plurality of communication channels including the communication channel selected as the usage channel;
The usage rate storage unit stores the plurality of channel usage rates corresponding to the plurality of communication channels, respectively.
The communication unit transmits information on the plurality of channel usage rates to the parent station,
The master station is a communication channel that is not used as the use channel in each of the plurality of meter-reading communication terminal stations based on the information of the plurality of channel usage rates transmitted from each of the plurality of meter-reading communication terminal stations. The communication system for meter reading according to claim 8, wherein information on the communication channel not used as the use channel is transmitted to each of the plurality of communication terminal stations for meter reading.

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