JP5715868B2 - Meter terminal, meter reading data collecting system and meter reading data collecting method - Google Patents

Description

  In the present invention, a large number of measuring instrument terminals installed in each consumer such as an integrating watt hour meter constitute a network, and the meter reading data is set at predetermined time intervals (on-time meter reading) or predetermined events (power failure, etc.). At the time of occurrence, by a multi-hop wireless communication, an aggregation device, a measuring instrument terminal that realizes automatic meter reading by transmitting to the host device and collecting it, and a meter reading data collecting system including the meter terminal, and The present invention relates to a meter reading data collection method.

  Patent Document 1 discloses a typical conventional technique in which meter reading data of electricity, gas, water, and the like are periodically sucked from the measuring instrument terminal to a host device by multi-hop wireless communication.

  The purpose of such automatic meter reading is to save the trouble of meter reading by switching the measured value of a measuring instrument installed at a high place or behind the wall from visual confirmation to automatic meter reading. Is. Accordingly, it is only necessary to collect data several times a day at most, and it is only necessary to distribute the meter reading data to each measuring instrument terminal while distributing the time.

  However, in order to provide a detailed service such as a time zone discount (for example, late night charge), a fine meter reading is required. On the other hand, when such a system, which will be started in a limited area, for example in a newly built housing complex, is becoming widespread, the number of measuring instrument terminals will be large, exceeding several million. End up. Therefore, if fine meter reading is performed on such a large number of measuring instrument terminals, traffic may be complicated and data loss or communication abnormality may occur.

  Therefore, in order to prevent such a problem, the present applicant has previously proposed Patent Document 2. According to the prior art, meter reading data of each measuring instrument terminal is collected by an aggregation device, and the aggregation device is configured as a gateway interposed between the multi-hop wireless communication network and a wired network. ing. Then, the gateway collects the meter reading data to the host device via the wired network, and distributes and transmits the data at a predetermined transmission timing for each of the gateways without adding the host device. This reduces the complexity of traffic near the host device. In this way, meter reading data can be collected from the gateway to the host device in a short time and with high reliability without a cost increase.

JP 2000-187793 A JP 2011-34388 A

  In the above-described Patent Document 2, in the meter reading data collection system including the meter terminals exceeding the millions, for example, even if the number of accommodating terminals of one gateway is 1000, the aggregated data from the gateway exceeding 1000s It is very effective for the collection at the host device. However, for the collection of meter reading data from the measuring terminal of nearly 1000 to the gateway, the number of hops from the gateway is stored in each measuring device terminal, and the terminal having a larger number of hops has a transmission timing of the meter reading data. It has been shown that securing the re-transmission time in the case of non-delivery is shown by making it early.

  By the way, even if the above-mentioned fine meter reading is performed, it is necessary to collect data within a predetermined short time from the reference timing of meter reading in order to charge and grasp the load. For example, it is necessary to perform a 30-minute meter reading at 0 and 30 minutes every hour and collect meter-reading data in an aggregation server within 5 minutes from the meter reading. On the other hand, even if the wired network from the gateway to the host device is high-speed, heavy aggregated data is transmitted from each of the many gateways in the wired network. Therefore, only about 2 minutes can be secured for collecting meter-reading data from the multiple measuring instrument terminals to the gateway.

  If it is attempted to collect meter reading data of a large number of measuring instrument terminals in the gateway via such a low-speed wireless LAN network in such a short time, traffic in the vicinity of the gateway is complicated. Here, by applying the method of Patent Document 2 to each measuring instrument terminal, each measuring instrument terminal combines the meter reading data sent from each measuring instrument terminal on the downstream side with its own meter reading data. It is also conceivable to send the aggregated data upstream. However, in that case, complicated processing for aggregating data is required for each measuring instrument terminal, which increases the terminal cost and requires time for aggregation, resulting in a case where aggregation cannot be performed within the time. There is a possibility.

  An object of the present invention is to stably and inexpensively read meter-reading data of all measuring instrument terminals accommodated in a network within a preset communicable time while avoiding traffic congestion near the aggregation device. A meter terminal capable of collecting, a meter reading data collecting system including the meter terminal, and a meter reading data collecting method.

The measuring instrument terminal of the present invention is installed in each consumer, and is a measuring instrument terminal that sequentially transmits meter reading data to the aggregation device via a multi-hop wireless communication network. The device terminals are divided into a plurality of groups with a predetermined number of hops as a boundary, and communication is allocated to each group according to the number of measuring instrument terminals to which each group belongs from a group with a large number of hops in a preset communication available time. Time is prescribed, and when the random waiting time has elapsed within the communication allocation time and the storage unit storing the communication allocation time, transmission of the meter reading data to the aggregation device is started. look including a communication control unit, the communication control unit, said each group Gi (i = 1,2,3, ···, n) the communication allocation time allocated to the WGi, La When the dumb addition time is WR, and the flag for determining whether the random addition time WR is valid or invalid is S (S = 1 or 0), the transmission start timing is set at each measuring instrument terminal in group i. The distributed transmission waiting time Wi from a predetermined reference time for defining is obtained from Wi = WR × S + TGi−1, where TGi−1 = WG1 + WG2 +... + WGi−1, and further the communication control The group Gi is configured such that the communicable time during which the meter-reading data can be collected is W0, the hop count of the boundary is Hth, the maximum hop count in the wireless communication network is Hmax, and the hop count of the target meter terminal is H. Gbig and Gsmall, and the communication allocation time for the group Gbig having a relatively large number of hops is Tb. ig, when the random delay time uniquely set in advance for each meter terminal is TD, the distributed transmission waiting time Wbig at the target meter terminal of the group Gbig having a relatively large number of hops and the target metering of the small group Gsmall The distributed transmission waiting time Wsmall at the terminal
Wbig = (Hmax−H) [Tbig ÷ (Hmax−Hth)]
Wsmall = (Hth−H) [(W0−Tbig− (TD × S)) ÷ Hth]
+ (TD × S) + Tbig
It is characterized by obtaining each from .

The meter reading data collection method of the present invention comprises a measuring instrument terminal installed in each consumer, a multi-hop wireless communication network, and an aggregation device that terminates the wireless communication network, In the meter reading data collection method in which meter reading data is sequentially transmitted from each measuring instrument terminal via the wireless communication network at a transmission start timing defined in advance, and aggregated by an aggregation device, the transmission start timing is Dividing all measuring instrument terminals constituting the wireless communication network into a plurality of groups with a predetermined number of hops as a boundary,
In the communication possible time set in advance, each group is assigned a communication allocation time according to the number of measuring instrument terminals to which the group has a large number of hops, and a random waiting time is set within the communication allocation time. It is set when the time elapses, and the communication allocation time allocated to each group Gi (i = 1, 2, 3,..., N) is WGi, the random addition time is WR, When a flag for determining whether the random additional time WR is valid or invalid is S (S = 1 or 0), a predetermined reference time for defining the transmission start timing in each measuring instrument terminal in group i Is determined from Wi = WR × S + TGi−1, where TGi−1 = WG1 + WG2 +... + WGi−1. The group Gi is set to Gbig and Gsmall, where W0 is the communicable time during which needle data can be collected, Hth is the number of hops in the boundary, Hmax is the maximum number of hops in the wireless communication network, and H is the number of hops of the target meter terminal. When the communication allocation time for the group Gbig having a relatively large number of hops is Tbig and the random delay time set in advance for each measuring instrument terminal is TD, the number of hops is relatively large. The distributed transmission waiting time Wbig at the target meter terminal of the group Gbig and the distributed transmission waiting time Wsmall at the target meter terminal of the small group Gsmall are:
Wbig = (Hmax−H) [Tbig ÷ (Hmax−Hth)]
Wsmall = (Hth−H) [(W0−Tbig− (TD × S)) ÷ Hth]
+ (TD × S) + Tbig
It is characterized by being obtained from each .

  According to the above configuration, a large number of measuring instrument terminals are installed in each consumer, and the measuring terminal is configured as a relay station with the other measuring instrument terminals interposed between the terminal and the aggregation device. In order to avoid traffic congestion in order to transmit meter-reading data to the aggregation device sequentially via the multi-hop wireless communication network, and to aggregate the aggregation data from the aggregation device, Specifies the start timing of the meter reading data transmission.

  That is, first, all measuring instrument terminals constituting the wireless communication network are divided into a plurality of groups with a predetermined number of hops as a boundary, and a preset communication available time is divided according to the number of terminals accommodated in each group. The communication allocation time for each group is defined. Thereby, almost equal communication time is assigned to each accommodating terminal regardless of the group. However, when transmission of a group with a large number of hops is in the latter half of the communication possible time, there may be a case where the transmitted meter reading data is in the hop at the end of the communication possible time. In addition, among the groups having a large number of hops, the communication allocation time of the group is allocated toward the beginning of the communicable time and stored in the storage unit. Further, in order to avoid the concentration of traffic (calling timing) within the allocated communication allocation time, the communication control unit determines the time point when a random waiting time has elapsed within the communication allocation time as each meter terminal. This is the final transmission start timing.

  Therefore, the meter reading data of all the meter terminals accommodated in the network (aggregation device) can be stably collected within the preset communicable time while avoiding the traffic congestion near the aggregation device. can do. Further, each measuring instrument terminal only needs to transmit meter-reading data at a timing determined by itself, and does not require complicated arithmetic processing, and can be realized at low cost.

  Furthermore, in the measuring instrument terminal of the present invention, the communication control unit sets the communication allocation time allocated to each group Gi (i = 1, 2, 3,..., N) as WGi, and adds a random addition time. Is set to WR, and the flag for determining whether the random addition time WR is valid or invalid is S (S = 1 or 0), in order to define the transmission start timing in each measuring instrument terminal in group i. Is determined from Wi = WR × S + TGi−1, where TGi−1 = WG1 + WG2 +... + WGi−1.

  According to said structure, the transmission start timing of each said measuring device terminal is defined as the dispersion | distribution transmission waiting time Wi from predetermined reference time, such as every hour 0 minute and 30 minutes. In the distribution, first, the random addition time WR is defined. However, the random addition time WR is not particularly provided when the number of terminals accommodated is extremely small because the group is a downstream terminal far from the aggregation device. In some cases, a flag S (S = 1 or 0) for determining whether the random addition time WR is valid or invalid is set, and the random addition time WR is multiplied.

  On the other hand, within the communicable time started from the reference time, each group Gi is preliminarily assigned with a communication allocation time WGi corresponding to the number of terminals accommodated in the group Gi as described above. Accordingly, for the i-th group Gi whose communication allocation time WGi is from the reference time, the total time TGi-1 of the communication allocation time for the group Gi-1 up to the (i-1) th before that is the reference waiting time. Will be included. That is, TGi−1 = WG1 + WG2 +... + WGi−1, and Wi = WR × S + TGi−1.

  As a result, with respect to the measuring instrument terminals in an arbitrary i-th group, the total number of terminals accommodated in the network (aggregation apparatus) within a preset communication possible time while avoiding the above-described traffic congestion. It is possible to define the transmission start timing at which meter-reading data of all the meter terminals can be collected.

  Further, in the measuring instrument terminal of the present invention, the communication control unit is configured such that the communicable time during which the meter-reading data can be collected is W0, the number of hops at the boundary is Hth, the maximum number of hops in the wireless communication network is Hmax, and the target The number of hops of the meter terminal is set to H, the group Gi is set to two of Gbig and Gsmall, and the communication allocation time for the group Gbig having a relatively large number of hops is set to Tbig. When the random delay time is TD, the distributed transmission waiting time Wbig at the target meter terminal of the group Gbig having a relatively large number of hops and the distributed transmission waiting time Wsmall at the target meter terminal of the small group Gsmall are expressed as Wbig = (Hmax−H) [Tbig ÷ (Hmax−Hth)], Wsmall = Hth-H) [(W0-Tbig- (TD × S)) ÷ Hth] + (TD × S) + and obtaining from each of Tbig.

  According to the above configuration, when the group Gi has two Gbig and Gsmall, the target measuring instrument terminal of the group Gbig having a relatively large number of hops first sets the communication allocation time Tbig to the group Gbig to the maximum. A unit communication allocation time (slot period) is obtained by dividing by the difference (Hmax−Hth) between the number of hops Hmax and the number of boundary hops Hth of the group. Next, the unit communication allocation time is multiplied by the difference (Hmax−H) between the maximum hop count Hmax and the hop count H of the local station to obtain the distributed transmission waiting time Wbig. Here, the number of hops Hth on the boundary is set such that Hmax ≧ Hth so that the number of accommodated terminals in a small group increases with respect to a group with a large number of hops. Therefore, in the target measuring instrument terminal of the group Gbig having a relatively large number of hops, the number of accommodated terminals decreases, so that the distributed transmission waiting time Wbig is simply the number of hops of the own station without performing random distribution. The timing corresponding to the amount of H is set.

  On the other hand, in the target measuring instrument terminal of the group Gsmall having a relatively large number of accommodated terminals and a relatively small number of hops, communication from the communicable time W0 in which the meter-reading data can be collected to the group Gbig having a large number of hops. By subtracting the allocation time Tbig and a value obtained by multiplying the delay time TD, which will be described later, by the flag S, a time Trend that can be used for randomization according to the hop count H is obtained. Next, by dividing the time Trend by the number of boundary hops Hth, a unit communication allocation time (slot period) of distribution is obtained. Subsequently, the unit communication allocation time is multiplied by the difference (Hth−H) between the number of hops Hth at the boundary and the number of hops H of the local station, and the first distributed transmission waiting time according to the number of hops H Wbig-1 is obtained.

  On the other hand, a specific delay time TD corresponding to the ID number and the like is set in advance for each measuring instrument terminal, and a value obtained by multiplying the delay time TD by the flag S is a second distributed transmission waiting time Wbig−. 2 and these distributed transmission waiting times Wbig-1 + Wbig-2 are set as the random addition time WR. Further, the communication allocation time Tbig for the group Gbig having a large number of hops becomes the basic delay total time TGi-1 for the group Gsmall having a small number of hops. Therefore, the distributed transmission waiting time Wsmall for the group Gsmall having a small number of hops can be sufficiently distributed.

  Furthermore, the meter-reading data collection system of the present invention comprises the measuring instrument terminal, a gateway as the aggregation device, and a host device connected to the gateway via a wired network, A first communication unit that receives the meter reading data transmitted from each of the measuring instrument terminals, and a plurality of meter reading data received by the first communication unit for each packet size of the wired communication line on the host device side. A data processing unit to be aggregated, a second communication unit for transmitting meter reading data aggregated by the data processing unit to the host device, and a delay time set in advance in the aggregation device from a reference time And a communication control unit that causes the second communication unit to start transmission to the host device when the time has elapsed.

  According to said structure, the said aggregation apparatus which collects meter-reading data from many measuring device terminals installed in each consumer is the gateway interposed between the said multihop radio | wireless communication network and a wired network And the gateway transmits meter reading data to the host device via the wired network, thereby configuring a meter reading data collection system.

  The gateway aggregates a plurality of meter reading data for each packet size of the wired communication line on the host device side when the collected meter reading data is transmitted to the host device. Therefore, each gateway can transmit meter-reading data to a host device in a short time. Further, since the communication control unit distributes the transmission timing from the gateway to the host device, it is possible to suppress the traffic complications in the vicinity of the host device. In this way, meter reading data can be collected in a short time and with high reliability as a result, without cost increase.

  Further, by using the gateway at the boundary between wired and wireless as the aggregation device, the degree of parallelism between the aggregation devices is high (the aggregation devices are not scattered in different layers), and the aggregation can be performed efficiently.

  Moreover, in the meter-reading data collection system of this invention, each said measuring device terminal communicates by wireless LAN specification, It is characterized by the above-mentioned.

  According to the above configuration, IEEE 802.11, which is the wireless LAN standard, uses CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) method to check for the presence of an empty channel and to transmit data. However, although data collision is avoided, if each measuring instrument terminal and the host apparatus communicate directly with each other using the TCP / IP protocol, since there is 1: 1 communication, there are many measuring instrument terminals. In this case, it takes a very long time to transmit meter reading data.

  Therefore, once the meter reading data is once aggregated and transmitted to the host device by the aggregation device including the gateway as described above, traffic in the vicinity of the host device can be suppressed.

  As described above, the measuring instrument terminal, meter reading data collecting system and meter reading data collecting method according to the present invention cause the metering data of a large number of measuring instrument terminals to be transmitted to the aggregation device via the multi-hop wireless communication network. At the time, each measuring instrument terminal is divided into a plurality of groups, the communication allocation time is defined according to the number of accommodated terminals, and the meter reading is performed at random timing from the group having a large number of hops within the communication allocation time. Send data.

  Therefore, the meter reading data of all the meter terminals accommodated in the network (aggregation device) can be stably obtained within the communication possible time set in advance while avoiding the traffic congestion in the vicinity of the aggregation device. Can be collected. Further, each measuring instrument terminal only needs to transmit meter-reading data at a timing determined by itself, and does not require complicated arithmetic processing, and can be realized at low cost.

It is a block diagram which shows schematic structure of the meter-reading data collection system which concerns on one Embodiment of this invention. It is a block diagram which shows one structural example of an aggregation apparatus. It is a figure for demonstrating the collection method of the meter-reading data of one Embodiment of this invention. It is a figure for demonstrating the collection method of the meter-reading data of one Embodiment of this invention. It is a figure for demonstrating the packet structure of the meter-reading data transmitted to the server apparatus from the said gateway. It is a figure for demonstrating the transmission procedure of the meter-reading data from the aggregation apparatus to the aggregation server in the meter-reading data collection system which concerns on one Embodiment of this invention. It is a front view which shows one structural example of a measuring device terminal. It is a block diagram which shows one structural example of the radio | wireless communication apparatus in the said measuring device terminal. It is a figure for demonstrating the preparation method of the transmission timing of the meter-reading data from a measuring device terminal to an aggregation apparatus in the meter-reading data collection system which concerns on one Embodiment of this invention. It is a flowchart for demonstrating in detail the creation method of the said transmission timing. It is a graph which shows distribution of the number of terminals with respect to the number of hops. It is a graph which shows the simulation result of this inventor who confirms the dispersion | distribution effect of the said transmission timing.

  FIG. 1 is a block diagram showing a schematic configuration of a meter reading data collection system according to an embodiment of the present invention. This meter-reading data collection system is connected to each of the consumers H1, H2,... (When collectively referred to as the reference symbol H hereinafter), respectively. , Hereinafter referred to by reference symbol U) constitutes a multi-hop wireless communication network, and transmits the meter-reading data to the aggregation server 1 which is a host device at a predetermined time or when a predetermined event occurs. It is a system that realizes automatic meter reading by collecting.

  The meter terminal U is realized as an integrated watt-hour meter in this embodiment, and performs communication according to the wireless LAN standard. Therefore, each measuring instrument terminal U performs 1: 1 wireless communication as indicated by reference signs A1, A2, A3,... In an ad hoc mode for terminal-to-terminal communication of a wireless LAN. Further, when each measuring instrument terminal U is activated (turned on), it monitors the surrounding radio wave condition as necessary, and the measuring terminal having the best communication quality (hanging destination: measuring instrument terminal in the example of FIG. 1). U2 with respect to U1, U5 with respect to U4, etc.) to connect, that is, join the network, and autonomously select a route to the aggregation device 3 that is the end of the wireless communication network, and the aggregation device 3 is created, and the meter reading data is transmitted in the ad hoc mode. From the route map, each measuring instrument terminal U can recognize the status of adjacent stations and the number of hops from the aggregation device 3 to its own station as described later.

  The aggregation device 3 connects a wireless communication network and a wired network 4 dedicated to a network operating company such as an electric power company. The aggregation server 1 is connected to the wired network 4. The aggregation device 3 is provided, for example, in a main utility pole, and the number of accommodation terminals is about several hundred to thousands. Further, the number of hops of each measuring instrument terminal U is several tens at the maximum, preferably 10 hops or less. Then, the aggregation device 3 provided in the lower layer of the aggregation server 1 aggregates the meter reading data from each measuring instrument terminal U under the umbrella as described later, and transmits it to the aggregation server 1.

  Although the hop destination of each measuring instrument terminal U determined as described above, the hop destination changes due to an increase, removal, or failure of the measuring instrument terminal U. Therefore, each measuring instrument terminal U periodically determines the radio wave condition and the hanging destination as described above, and changes the route map. It is to be noted that radio wave condition data is transmitted from each measuring instrument terminal U side, a route map is created (determining the hanging destination) on the aggregation server 1 or the aggregation apparatus 3 side, and each measuring instrument terminal U is sent to each weighing instrument terminal U. You may make it set.

  In the present embodiment, the aggregation device 3 is a gateway provided at the boundary between the wired network 4 and the wireless network, that is, at the end of the multi-hop wireless communication network. You may provide in the middle of a multihop radio | wireless communication network, and may be provided in the some step of the middle and this aggregation apparatus 3. FIG. However, by using the gateway at the boundary between wired and wireless as the aggregation device 3, the degree of parallelism between the aggregation devices 3 is high (the aggregation devices 3 are not scattered in different layers), and the aggregation is performed efficiently. be able to.

  FIG. 2 is a block diagram illustrating a configuration example of the aggregation device 3. The aggregation device 3 communicates with the aggregation server 1 via the wireless LAN standard (IEEE 802.11) interface 11 that communicates with each of the measuring instrument terminals U, the communication control unit 12, and the wired network 4. Wired LAN (Ethernet (registered trademark)) standard (IEEE 802.3) interface 13, its communication control unit 14, and a plurality of meter reading data from each measuring instrument terminal U received by the interface 11 are collected. A data processing unit 15 that aggregates each packet size of the wired network 4 (communication line) on the server 1 side, a work memory 16 that is used for the data processing, and a control that controls the overall operation of the aggregation device 3 And a clock unit 18 that holds time information serving as a reference for the operation of the control unit 17.

  The interface 11 and the communication control unit 12 constitute a first communication unit that receives the meter reading data individually transmitted by the multi-hop from each measuring instrument terminal U, and the interface 13 and the communication control unit 14 constitutes a second communication unit that transmits the meter reading data aggregated by the data processing unit 15 to the aggregation server 1. Note that multi-hop wireless communication is not limited to a wireless LAN, and other standards other than the wireless LAN may be used. Similarly, standards other than wired LAN may be used for wired communication.

  In the meter reading data collection system configured as described above, FIG. 3 and FIG. 4 are diagrams for explaining the meter reading data collecting method according to the embodiment of the present invention. As shown in FIG. 3, each of the measuring instrument terminals U11 to U1m; U21 to U2n; Ux1 to Uxk performs a meter reading of the built-in integrating wattmeter at, for example, 0 and 30 minutes per hour, for example, 32 bytes of the data Are transmitted using a wireless LAN (IEEE 802.11) protocol. At this time, each measuring terminal U uses the CSMA / CA method to check the free state of the radio channel to be used, and as shown in FIG. The transmission start timing is set so that the larger the number of groups, the faster the random transmission starts. The meter reading data transmission operation by the measuring instrument terminal U will be described in detail.

  On the other hand, the meter reading data transmitted from each measuring instrument terminal U arrives at the aggregation devices A, B,..., X, is received by the interface 11, and is sent from the communication control unit 12 to the data processing unit 15. Are sequentially stored in the work memory 16. As these first steps, for example, 120 seconds is set for collecting meter-reading data from 1000 measuring instrument terminals U. The meter processing data collected in this way is collected by the data processing unit 15 into a single packet using the work memory 16 from the communication control unit 14 through the interface 13 to the aggregation server 1. Send sequentially. Thus, the collection of the collected meter reading data from tens of thousands of collecting devices 3 requires a time of, for example, 180 seconds as the second stage. Thus, the automatic collection of meter reading data is completed in a total of 300 seconds.

  Note that the control unit 17 of each aggregation device 3 does not reach within the prescribed 120 seconds in the first stage, and discards the meter reading data that has arrived thereafter. For this reason, for the measuring instrument terminal for which the meter reading data has not been delivered, the aggregation server 1 individually requests transmission of the non-delivery meter reading data after a predetermined interval period after the second stage. Then, the request is transmitted to the target measuring instrument terminal via the multi-hop communication path, and the backup meter reading is performed to sequentially transfer the returned meter reading data to the aggregation server 1.

  By the way, when transmitting the meter reading data from the aggregation device 3 to the aggregation server 1, the communication control unit 14 uses the wired network 4 used for the transmission so that the aggregation server 1 collects the meter reading data with high reliability. The communication is performed using the TCP / IP protocol capable of performing the data arrival guarantee communication. Therefore, the data processing unit 15 converts the 32-byte meter reading data from each measuring instrument terminal U to 1500 bytes, which is a size corresponding to the maximum MTU of the transmission standard (IEEE802.3) in the TCP / IP protocol. The data for 44 units is collected into one packet by the measuring instrument terminal U so as to correspond to the above.

  FIG. 5A is a diagram illustrating a structure of a transmission packet in which meter-reading data transmitted from the aggregation device 3 to the aggregation server 1 is aggregated. First, data D01 representing the message type and data D02 representing the number of data are provided at the top, followed by actual meter reading data D1, D2,... (Up to D44 as described above), Finally, an end mark D03 is inserted. As described above, the meter reading data per case is 32 bytes, the maximum is 1408 bytes for 44 units, the data D01, D02, D03 are 4,1,1 bytes respectively, and the total number of transmitted packets is 1414 at maximum. It becomes a byte. Add 20 or 20 bytes for each of the IP and TCP headers to 1500 bytes or less. The data D01 representing the message type represents one of metering data transmission start (first packet), transmission (intermediate packet) and transmission completion (last packet), and the data D02 representing the number of data is It becomes a numerical value of 1-44.

  Then, as shown in FIG. 6, the control unit 17 waits for a delay time τ1, τ2, τ3,... Preset in each aggregation device 3 from a reference time (the meter reading timing) t0. Then, transmission of the aggregated packet to the aggregation server 1 is started. Specifically, each measuring instrument terminal U is given an ID number or an IP address given in advance as a unique number of serial numbers. These are divided by, for example, 15 and the remainder is divided into 15 groups of 0 to 14, and the delay time shifted by 1 second for each group is preset in the communication control unit 14 or controlled. The unit 17 controls the timing. When one packet is transmitted, the next packet is transmitted 15 seconds after the transmission timing has made one round for all groups.

Therefore, if the number of accommodated data of one packet is 44 and the number of accommodated terminals of the aggregation device 3 is 500, each aggregation device 3 needs to transmit 12 packets of data for each meter reading, If the transmission cycle is 15 seconds, the required transmission time is 180 seconds. If the total number of terminals is 12 million, the number of aggregation devices 3 is 24,000, and when the number is dispersed in the 15 seconds, 0.625 msec per unit is obtained. Therefore, since one aggregation device 3 transmits one packet per 0.625 seconds, the number of packets per second is
1 [second] /0.625 [msec / packet] = 1600 [packet]
Thus, assuming that the processing capacity of the aggregation server 1 is 3000 PPS, processing by one unit is possible.

  In this way, the data processing unit 15 of the aggregation device 3 aggregates a plurality of meter reading data D1, D2,... For each packet size of the wired communication line 4 on the aggregation server 1 side. , Meter reading data D1, D2,... Can be transmitted to the aggregation server 1 in a short time. Furthermore, since the communication control unit 14 distributes the transmission timing from the aggregation device 3 to the aggregation server 1, it is possible to suppress the traffic in the vicinity of the aggregation server 1. As a result, the meter reading data D1, D2,... Can be collected in the aggregation server 1 in a short time and with high reliability without increasing costs.

  In particular, in the present embodiment, each measuring instrument terminal U performs communication according to IEEE 802.11, which is a wireless LAN standard. In that case, each measuring terminal U uses a CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) method to check for the presence of an empty channel and transmit data, thereby avoiding data collision. However, if each measuring instrument terminal U and the aggregation server 1 communicate directly with each other using the TCP / IP protocol, the communication is 1: 1, and therefore when there are many measuring instrument terminals U, the meter reading data D1 , D2,... Takes a very long time. Therefore, as described above, the aggregation device 3 including the gateway once aggregates the meter reading data and transmits the collected data to the aggregation server 1 that is the host device, thereby suppressing traffic in the vicinity of the aggregation server 1.

  On the other hand, FIG. 7 is a front view showing a configuration example of the measuring instrument terminal U. This measuring instrument terminal U is configured by arranging a load switch 7, a watt hour meter 8, and a wireless communication device 5 from the terminal block 6 side to which each distribution line in the house is connected. The watt-hour meter 8 measures the accumulated power amount every predetermined period, for example, every 30 minutes, and the meter reading data is preset at the meter terminal U by the wireless communication device 5 as will be described later. The data is transmitted to the aggregation device 3 to which the own device belongs and transferred to the aggregation server 1. On the other hand, from the aggregation server 1, control data for performing the opening / closing of the load switch 7, the backup meter reading for resending the non-delivery meter reading data, and the like is transmitted via the aggregation device 3 as necessary. It is transmitted toward the communication device 5.

  FIG. 8 is a block diagram illustrating a configuration example of the wireless communication device 5. The wireless communication device 5 controls the communication with the wireless communication unit 21 of the wireless LAN, and receives meter reading data from the wireless communication control unit 22 that is a communication control unit, the clock unit 23, and the watt hour meter 8. An interface 24, an interface 25 for transmitting control information to the load switch 7, an in-machine communication control unit 26 for controlling communication with the watt hour meter 8 and the load switch 7, and backup of the meter reading data A memory 27 for storing and a memory 28 for storing the route table are provided.

  The in-flight communication control unit 26 receives meter reading data from the watt hour meter 8 through the interface 24 at a predetermined meter reading time, for example, every minute, in response to the internal clock of the clock unit 23. The data is stored in the memory 27 as indicated by reference numeral 27a. The wireless communication control unit 22 reads the meter reading data in response to the internal clock, and reads the data between the meter reading timings of 0 minutes and 30 minutes per hour when the transmission timing is obtained as described later. Transmit from the wireless communication unit 21. In response to the internal clock, the wireless communication unit 21 determines the hop destination by looking around the surroundings as described above at predetermined time intervals, and transmits the meter reading data to the hop destination and receives the other The meter reading data from the weighing terminal U is transferred.

  In each measuring instrument terminal U configured as described above, it should be noted in the wireless communication control unit 22 of the present embodiment that when each measuring instrument terminal U sequentially transmits meter-reading data, the measuring device terminal U is in the vicinity of the aggregation device 3. Transmission is performed at a timing that can avoid traffic congestion. Specifically, in response to the internal clock of the clock unit 23 as described above, the meter reading data collected by the in-flight communication control unit 26 every minute and stored in the memory 27 is transmitted to the wireless communication control unit. When the meter reading timings of 0 and 30 minutes per hour are reached, the meter 22 collects the meter reading data to be transmitted to the aggregation server 1. The wireless communication control unit 22 starts transmitting the meter-reading data at a transmission timing corresponding to the number of hops from the aggregation device 3 to the own station that can be obtained from the route table stored in the memory 28.

  FIG. 9 is a diagram for explaining a transmission timing generation method according to the present embodiment. First, it should be noted in the present embodiment that each measuring instrument terminal U is divided into a plurality of groups Gi with a predetermined number of hops as a boundary. FIG. 9 shows a simple example. The wireless communication network is configured by three serial routes each without branching, and the first route is a measuring instrument terminal in order from the upstream (aggregation device 3) side. U11-U12-U13-U14-U15, the second route is composed of measuring instrument terminals U21-U22-U23-U24-U25, and the third route is measuring instrument terminals U31-U32-U33-U34- It is composed of U35. In FIG. 9, each measuring instrument terminal U is most simply divided into two groups Gsmall and Gbig, and measuring terminals U11-U12-U13-U14 on the upstream side with a small number of hops; U21 -U22-U23-U24; U31-U32-U33-U34 form a group Gsmall, and downstream meter terminals U-15, U-25, U-35 having a large number of hops form a group Gbig.

  Next, it should be noted in the present embodiment that, as described above, the time W0 (120 seconds in the above example) allowed to transmit meter reading data from each measuring instrument terminal U to the aggregation device 3 is communicated. When the possible time is set, each group Gi is defined with a communication allocation time WGi corresponding to the number of measuring instrument terminals to which the group Gi belongs. Furthermore, in the group Gbig having a large number of hops, the arrival time of the meter reading data D is expected to be relatively long, and therefore, the group Gbig is assigned to the first half of the time W0. For example, if the number ratio in the groups Gsmall and Gbig is 9: 1, the group Gbig is assigned the first 12 seconds, and the group Gsmall is assigned the second 108 seconds (4: 1 in the example of FIG. 9). And 24 seconds and 96 seconds). In this way, it is possible to cope with re-transmission at the time of non-delivery.

  Furthermore, it should be noted in the present embodiment that the terminals belonging to each group Gi within the communication allocation time WGi, when the random waiting time WR has passed, the meter reading data to the aggregation device 3 It is to start transmission.

  FIG. 10 is a flowchart for explaining in detail the transmission timing generation method of the present embodiment by the wireless communication control unit 22. First, in step S1, the route table stored in the memory 28 is read. In step S2, the route table is analyzed, and the hop count H of the own station is calculated. In step S3, the local station's hop count H is compared with the preset boundary hop counts Hth1, Hth2,... (In the above example, only Hth1 is collectively referred to as reference symbol Hth below). Then, the group Gi (i = 1, 2, 3,..., N) to which the own station belongs is determined. In step S4, a random additional time WR is obtained. In step S5, the group waiting time TGi-1 assigned to the group i to which the own station belongs is obtained from the communication assignment time WGi. Thereafter, in step S6, each meter terminal U obtains the distributed transmission waiting time Wi from a predetermined reference time such as 0 minutes or 30 minutes per hour.

That is,
Wi = WR × S + TGi−1 (1)
It is. However, S is a flag for determining whether the random addition time WR is valid or invalid, and S = 1 or 0. This is because the group Gi is a terminal on the downstream side far from the aggregation device 3 and the number of accommodated terminals is very small. In particular, the random addition time WR may not be provided.

Then, among the communicable times W0 started from the reference time, the communication allocation time WGi corresponding to the number of accommodated terminals of the group Gi is sequentially allocated to each group Gi in advance as described above. For the i-th group Gi whose communication allocation time WGi is from the reference time, the total time TGi-1 of the communication allocation time for the group Gi-1 up to the previous (i-1) th group is included as the reference waiting time. Will be. there,
TGi-1 = WG1 + WG2 + ... + WGi-1 (2)
It is.

  The waiting time Wi (transmission timing) created as described above is basically unchanged when there is no change in the route table, and is updated every time the route table is updated and stored in the memory 28 in advance. May be. However, it may be obtained each time transmission is performed, for example, by changing the additional time WR for performing dispersion within the communication allocation time WGi. Furthermore, in this embodiment, the waiting time Wi (transmission timing) is created by the wireless communication control unit 22 of the measuring instrument terminal U. However, the aggregation device grasps the entire wireless communication network. 3 or the aggregation server 1 and may be set in each measuring instrument terminal U.

  On the other hand, when the waiting time Wi (transmission timing) is created on the wireless communication control unit 22 side of the measuring instrument terminal U as described above, it is necessary to set appropriately if the boundary hop number Hth or the like is changed, The range of the group waiting time TGi-1 that changes with the number of accommodated terminals and the additional time WR set within the communication allocation time WGi is also preferably set according to the terminal environment around the own station.

  As described above, according to the measuring instrument terminal U and the meter reading data collection method of the present embodiment, each measuring instrument terminal U sequentially sends meter reading data to the aggregation device 3 via the multi-hop wireless communication network. When transmitting, first, all measuring instrument terminals U configuring the wireless communication network are divided into a plurality of groups Gi with a predetermined hop number Hth as a boundary, and a preset communicable time W0 is accommodated in each group Gi. The communication allocation time WGi for each group Gi is defined according to the number of terminals to be performed. As a result, almost equal communication time is allocated to each accommodating terminal regardless of the group.

  However, if the transmission of a group with a large number of hops is in the latter half of the communicable time W0, the transmitted meter reading data may be in hop at the end of the communicable time W0. As shown in FIG. 4, the communication allocation time WGi of the group Gi is assigned to the beginning of the communicable time W0 from the group having the large number of hops H in each group Gi. Further, in order to avoid the concentration of traffic (calling timing) within the allocated communication allocation time WGi, the time point at which the random waiting time WR has elapsed within the communication allocation time WGi is determined. The final transmission start timing (waiting time Wi) is used.

  Accordingly, the meter reading data of all the meter terminals U accommodated in the network (aggregation device 3) can be obtained within the preset communication available time W0 while avoiding the traffic congestion in the vicinity of the aggregation device 3. It can be collected stably. Further, each measuring instrument terminal U only needs to transmit meter-reading data at a timing determined by itself, and does not require complicated calculation processing, and can be realized at low cost.

  Further, by obtaining such a waiting time Wi by the above equation 1, a communication set in advance while avoiding the traffic congestion as described above to the measuring instrument terminal in an arbitrary i-th group Gi. Within a possible time, it is possible to define a transmission start timing at which meter-reading data of all measuring instrument terminals accommodated in the network (aggregation device 3) can be collected.

  In the above description, the division of the group Gi is determined by the wireless communication control unit 22 by comparing the actual hop count H and the boundary hop count Hth. In this case, in the claims The storage unit is the wireless communication control unit 22 and the memory 28. However, the division of the group Gi may be determined by the upstream aggregation server 1 or the aggregation device 3 and set in each measuring instrument terminal U by a control signal or the like. It becomes a memory | storage part in a claim. In addition, the grouping as described above is an example that can be dynamically changed in response to a change in the number of hops H or the like. However, as in the following specific example, the group Gi is divided into two groups, Gsmall and Gbig. When dividing into only a small number of groups, it may be fixed with a dip switch or the like when installing the measuring instrument terminal U. In that case, the dip switch or the like is connected to the storage unit in the claims. Become.

  A more specific algorithm for creating the waiting time Wi (transmission timing) will be described as follows. In the following description, similarly to FIG. 9 described above, the boundary hop number Hth is described as one of Hth1, that is, the group Gi is described as two of Gsmall and Gbig. Needless to say, it is good. As described above, the communicable time during which meter-reading data can be collected is W0, and the maximum number of hops in the wireless communication network is Hmax, the number of hops of the target measuring device terminal is H, and the group Gbig having a large number of hops H Let Tbig be the communication allocation time for. On the other hand, a delay time for randomization that is uniquely set in advance in each measuring instrument terminal U is newly defined as TD.

  The settable range of each parameter is, for example, Hmax = 1 to 127, Tbig = 1 to 590 [seconds], TD = 10 to 590 [seconds], and W0 = 20 to 600 [seconds]. Specifically, as shown in FIG. 11, the distribution relationship of the number of meter terminals with respect to the number of hops H is biased toward a range where the number of hops is small (approximately 1 to 10 hops). For example, when Hth = 10 is set as the number of hops at the boundary, Gsmall: Gbig is often about 9: 1. When W0 = 120 [seconds], Tbig = 12 [seconds] It is. Also, TD = 60 [seconds], and the maximum hop count Hmax is about 20 in practice.

Then, the distributed transmission waiting time Wbig at the target meter terminal of the group Gbig having a large number of hops and the distributed transmission waiting time Wsmall at the target meter terminal of the group Gsmall having a small number of hops,
Wbig = (Hmax−H) [Tbig ÷ (Hmax−Hth)]
Wsmall = (Hth−H) [(W0−Tbig− (TD × S)) ÷ Hth] + (TD × S) + Tbig
It prescribes.

  That is, when the group Gi is Gbig and Gsmall, the target meter terminal of the group Gbig having a relatively large number of hops first sets the communication allocation time Tbig to the group Gbig to the maximum hop count Hmax and the group hop count. A unit communication allocation time (slot period) is obtained by dividing by the difference (number Hmax−Hth) from the number of boundary hops Hth. Next, the unit communication allocation time is multiplied by the difference (Hmax−H) between the maximum hop count Hmax and the hop count H of the local station to obtain the distributed transmission waiting time Wbig. Here, as described above, the boundary hop count Hth is set such that Hmax ≧ Hth so that the number of accommodated terminals of the small group Gsmall is larger than the group Gbig having the large number of hops. Therefore, in the target measuring instrument terminal of the group Gbig having a relatively large number of hops, the number of accommodated terminals decreases, so that the distributed transmission waiting time Wbig is simply the number of hops of the own station without performing random distribution. The timing corresponding to the amount of H is set.

  On the other hand, in the target measuring instrument terminal of the group Gsmall having a relatively large number of accommodated terminals and a relatively small number of hops, communication from the communicable time W0 in which the meter-reading data can be collected to the group Gbig having a large number of hops. By subtracting the allocated time Tbig and a value obtained by multiplying the delay time TD, which will be described later, by the flag S, a time TD ′ that can be used for randomization according to the number of hops H is obtained. Next, by dividing the time TD 'by the number of boundary hops Hth, a unit communication allocation time (slot period) of distribution is obtained. Subsequently, the unit communication allocation time is multiplied by the difference (Hth−H) between the number of hops Hth at the boundary and the number of hops H of the local station, and the first distributed transmission waiting time according to the number of hops H Obtain Wsmall-1.

  On the other hand, each measuring instrument terminal U is also preset with a unique delay time TD corresponding to its ID number, and the second distributed transmission waiting time Wsmall is obtained by multiplying the delay time TD by the flag S. −2 and the distributed transmission waiting time Wsmall-1 + Wsmall-2 is set as the random addition time WR. Further, the communication allocation time Tbig for the group Gbig having a large number of hops becomes the basic delay total time TGi-1 for the group Gsmall having a small number of hops. Therefore, the distributed transmission waiting time Wsmall for the group Gsmall having a small number of hops can be sufficiently distributed.

  FIG. 12 is a graph showing the simulation results of the present inventors. In this simulation, in an environment with 200 measuring instrument terminals, assuming an environment in which 90% of terminals are 10% and 10% of terminals are 11 to 20 hops, the communicable time W0 is 120 [seconds]. ]. FIG. 12 (a) shows a case in which transmission is performed in order from the terminal with the largest number of hops. In the first half (0 to 60 seconds) and the second half (60 to 120 seconds), it is per time (in 10 second units). The traffic bias is large. In particular, since the allocation per hop is 6 seconds, it is understood that the peak of 80 to 120 seconds when a terminal of 6 to 7 hops starts transmission is large.

  FIG.12 (b) has shown the example which prescribed | regulated communication allocation time WGi from the distribution of the number of terminals with respect to the number of hops before FIG.12 (a), and shows per said time (when it sees in a unit of 10 seconds). It can be seen that while the traffic bias is reduced, the traffic peaks are still large (concentrated in 60-100 seconds). Furthermore, FIG. 12C is obtained by adding a random waiting time to FIG. 12B, and it is understood that the peak is greatly reduced.

DESCRIPTION OF SYMBOLS 1 Aggregation server 3 Aggregation apparatus 4 Wired network 5 Wireless communication apparatus 7 Load switch 8 Electricity meter 11 Wireless LAN standard (IEEE802.11) interface 12, 14 Communication control part 13 Wired LAN standard (IEEE802.3) interface Face 15 Data processing unit 16 Work memory 17 Control unit 18 Clock unit 21 Wireless LAN wireless communication unit 22 Wireless communication control unit 23 Clock unit 24 Interface (for electricity meter)
25 Interface (for load)
26 In-machine communication control unit 27 Memory (for meter reading data)
28 memory (for route table)
H1, H2, ... Consumers U1, U2, ... Measuring instrument terminals U11 to U1m; U21 to U2n; Ux1 to Uxk Measuring instrument terminals

Claims (4)

In the measuring instrument terminal that is installed in each consumer and sequentially transmits meter reading data to the aggregation device via the multi-hop wireless communication network,
All the measuring instrument terminals constituting the wireless communication network are divided into a plurality of groups with a predetermined number of hops as a boundary, and each group has a large number of hops from the group having a large number of hops in a predetermined communication time. A communication allocation time according to the number of measuring instrument terminals to be specified, and a storage unit storing the communication allocation time;
In the communication allocation time, when the random wait time has elapsed, it is seen including a communication control unit that initiates a transmission to the aggregation device of the meter reading data,
The communication control unit sets the communication allocation time assigned to each group Gi (i = 1, 2, 3,..., N) as WGi, sets the random addition time as WR, and makes the random addition time WR effective. When the flag for determining whether or not to be invalid is S (S = 1 or 0), the distributed transmission waiting time from a predetermined reference time for defining the transmission start timing at each measuring instrument terminal in group i Wi
Wi = WR × S + TGi−1
However,
TGi-1 = WG1 + WG2 + ... + WGi-1
From
The communication control unit is configured such that the communicable time during which the meter-reading data can be collected is W0, the number of hops at the boundary is Hth, the maximum number of hops in the wireless communication network is Hmax, and the number of hops of the target meter terminal is H. When the group Gi is Gbig and Gsmall, the communication allocation time for the group Gbig having a relatively large number of hops is Tbig, and the random delay time uniquely set in advance for each measuring instrument terminal is TD. , The distributed transmission waiting time Wbig at the target meter terminal of the group Gbig having a relatively large number of hops and the distributed transmission waiting time Wsmall at the target meter terminal of the small group Gsmall,
Wbig = (Hmax−H) [Tbig ÷ (Hmax−Hth)]
Wsmall = (Hth−H) [(W0−Tbig− (TD × S)) ÷ Hth]
+ (TD × S) + Tbig
A measuring terminal characterized by being obtained from each . The weighing instrument terminal according to claim 1 , a gateway as the aggregation device, and a host device connected to the gateway via a wired network,
The gateway is
A first communication unit that receives the meter-reading data transmitted from each of the measuring instrument terminals;
A data processing unit that aggregates a plurality of meter-reading data received by the first communication unit for each packet size of the wired communication line on the host device side;
A second communication unit that transmits the meter reading data collected by the data processing unit to the host device;
Meter reading data, comprising: a communication control unit that causes the second communication unit to start transmission to a host device when a delay time preset in the aggregation device has elapsed from a reference time Collection system. 3. The meter-reading data collection system according to claim 2 , wherein each measuring instrument terminal performs communication according to a wireless LAN standard. A measuring instrument terminal installed in each consumer, a multi-hop wireless communication network, and an aggregation device serving as a terminal of the wireless communication network, each of which is preliminarily transmitted from the measuring terminal. At the start timing, the meter reading data is sequentially transmitted via the wireless communication network, and the meter reading data collecting method is configured to aggregate the data by the aggregation device.
The transmission start timing is
Dividing all measuring instrument terminals constituting the wireless communication network into a plurality of groups with a predetermined number of hops as a boundary,
In the communication possible time set in advance, each group is prescribed a communication allocation time according to the number of measuring instrument terminals to which it belongs from a group with a large number of hops,
It is set when a random waiting time elapses within the communication allocation time ,
The communication allocation time allocated to each group Gi (i = 1, 2, 3,..., N) is WGi, the random addition time is WR, and the random addition time WR is enabled or disabled. When the flag that determines whether or not is S (S = 1 or 0), at each measuring instrument terminal in group i, the distributed transmission waiting time Wi from a predetermined reference time for defining the transmission start timing is:
Wi = WR × S + TGi−1
However,
TGi-1 = WG1 + WG2 + ... + WGi-1
Further,
The communicable time in which the meter-reading data can be collected is W0, the boundary hop count is Hth, the maximum hop count in the wireless communication network is Hmax, the target meter terminal hop count is H, and the group Gi is Gbig. Gsmall, and when the communication allocation time for the group Gbig having a relatively large number of hops is Tbig and the random delay time uniquely set in advance for each meter terminal is TD, the number of hops is relatively large. The distributed transmission waiting time Wbig at the target measuring terminal of the large group Gbig and the distributed transmission waiting time Wsall at the target measuring terminal of the small group Gsmall are:
Wbig = (Hmax−H) [Tbig ÷ (Hmax−Hth)]
Wsmall = (Hth−H) [(W0−Tbig− (TD × S)) ÷ Hth]
+ (TD × S) + Tbig
The meter reading data collection method characterized by each being required from .