JP2011034388A - Meter reading data collection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To collect meter reading data at low cost, in a short period of time, and highly reliably, in a system in which a plurality of measuring terminals transmit measured data to a host device using multihop wireless communication. <P>SOLUTION: A plurality of gateways 3 are arranged as consolidating terminals at a lower layer of a server 1 as a host device, while each of measuring terminals U11-U1m wirelessly transmits the measured data independently using wireless LAN protocol. At the gateway 3, the measured data are consolidated in packets each having a packet size of TCP/IP protocol of the server 1. Then, the gateways 3 initiate sending the consolidated packets to the server 1 distributedly one another, after a preset delay time passes over that is set for each gateway 3 in advance. Accordingly, traffic is reduced in the vicinity of the server 1, data loss and abnormal communication caused by intricate communications are prevented, and the server 1 can collect measured data without increasing cost needlessly, in a short period of time, and highly reliably. <P>COPYRIGHT: (C)2011,JPO&INPIT

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.). The present invention relates to a system that realizes automatic meter reading by transmitting to a host device by multi-hop wireless communication and collecting it at the time of occurrence.

  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.

JP 2000-187793 A

  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 many measuring instrument terminals, traffic in the vicinity of the host device may be complicated, and data loss or communication abnormality may occur. Therefore, in order to prevent such a problem, it is typically considered to add a host device that collects meter reading data. However, there are problems that the cost increases and the operability of the system decreases.

  An object of the present invention is to provide a meter reading data collection system capable of collecting meter reading data in a short time and with high reliability while suppressing cost.

  The meter reading data collection system of the present invention includes a measuring instrument terminal installed in each consumer, a gateway connected to the measuring instrument terminal via a wireless communication network, and meter reading data transmitted from each measuring instrument terminal in a multi-hop manner. And a host device connected to the gateway via a wired network, and an aggregation terminal provided in the wireless communication network, the aggregation terminal receiving meter reading data individually transmitted from the measuring instrument terminals A first communication unit, a data processing unit that aggregates a plurality of meter reading data received by the first communication unit for each packet size of the communication line on the host device side, and a meter reading that is aggregated by the data processing unit When a delay time set in advance in the aggregation terminal has elapsed from the second communication unit that transmits data to the host device and the reference time , Characterized in that it comprises a communication control unit and for starting transmission to the host device to the second communication unit.

  According to the above configuration, a large number of measuring instrument terminals installed in each consumer constitute a network, and the meter reading data is determined by multi-hop wireless communication every predetermined time or at a predetermined event occurrence time. In a system that realizes automatic meter reading, etc., by transmitting to the gateway and then transmitting from the gateway to the host device via a wired network and collecting the data, each meter terminal transmits the meter reading data individually On the other hand, an aggregation terminal is provided in at least the wireless communication network, and the meter reading data is aggregated and transmitted to the host device by the aggregation terminal.

  Therefore, the aggregation terminal includes a first communication unit that receives meter reading data individually transmitted from each measuring instrument terminal, and a plurality of meter reading data received by the first communication unit on the host device side. A data processing unit that aggregates each packet size of the communication line, and a second communication unit that transmits the meter reading data aggregated by the data processing unit to the host device are provided individually from each of the measuring instrument terminals. The transmitted meter-reading data can be collected and transmitted for each packet size of the communication line on the host device side. Further, a communication control unit for controlling the second communication unit is provided, and the communication control units are mutually distributed when a delay time set in advance in the aggregation terminal has elapsed from a reference time. , Causing the second communication unit to start transmission toward the host device.

  Therefore, by reading the meter at a predetermined time or a predetermined cycle, a large number of meter reading data that are simultaneously generated and transmitted individually at a number of measuring instrument terminals are aggregated at the aggregation terminal and transferred to the host device. Therefore, it is possible to suppress traffic near the host device and prevent data loss and communication abnormality due to complications. In addition, since the communication control unit adjusts the transmission timing of the aggregated meter reading data from the second communication unit so as not to overlap, this also suppresses traffic complications near the host device. it can. In this way, meter reading data can be collected in a short time and with high reliability as a result, without cost increase.

  Further, in the meter-reading data collection system of the present invention, each of the measuring instrument terminals performs communication according to a wireless LAN standard, and the aggregation terminal includes a wireless LAN line on the measuring instrument terminal side and a wired LAN line on the host device side. The gateway is interposed between the two.

  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.

  Thus, as described above, the meter reading data is once aggregated and transmitted to the host device by the aggregation terminal including the gateway, so that traffic in the vicinity of the host device can be suppressed. Further, by using the gateway at the boundary between wired and wireless as an aggregation terminal, the degree of parallelism between the aggregation terminals is high (the aggregation terminals are not scattered in different layers), and the aggregation can be performed efficiently.

  Furthermore, in the meter-reading data collection system of this invention, in the said gateway, a said 2nd communication part communicates the said wired LAN line between the said host apparatuses with a TCP / IP protocol, and this 2nd communication The unit establishes a TCP session with the host device for each predetermined period at a timing shifted from each other between the measuring instrument terminals, and reads the meter reading data collected by the data processing unit for each period. It is characterized by transmitting each packet.

  According to the above configuration, the second communication unit that communicates with the host device in the aggregation terminal, that is, the gateway provided at the boundary between wired and wireless, communicates the wired LAN line with the TCP / IP protocol. The second communication unit establishes a TCP session with the host device at a predetermined cycle with a timing shifted from each other between the measuring device terminals, and aggregates the data processing unit at each cycle. The meter reading data is transmitted one packet at a time.

  Therefore, although it is necessary to establish a TCP session for each packet, each meter terminal can transmit meter-reading data equally, and a specific terminal can be prevented from occupying a TCP session for a long time.

  In the meter-reading data collection system of the present invention, in the gateway, the second communication unit communicates the wired LAN line with the host device using a TCP / IP protocol, and the gateway is activated. When the TCP session is established, the TCP session is maintained until all received meter reading data is transmitted to the host device.

  According to the above configuration, the second communication unit that communicates with the host device in the aggregation terminal, that is, the gateway provided at the boundary between wired and wireless, communicates the wired LAN line with the TCP / IP protocol. Once the TCP session is established, the TCP session is maintained (not disconnected) until all the received meter reading data is transmitted to the host device.

  Therefore, the number of TCP session establishments can be reduced, transmission can be completed in a shorter time, and data reliability can be improved.

  Furthermore, in the meter-reading data collection system of the present invention, the second communication unit always maintains a TCP session with the host device.

  According to said structure, the 2nd communication part which communicates with a host apparatus maintains a TCP session always (it does not cut | disconnect).

  Therefore, the number of packets for establishing a TCP session can be reduced, and the total number of packets can be reduced.

  Moreover, in the meter-reading data collection system of this invention, each said meter terminal has a memory | storage part which memorize | stores the hop number from the said gateway, and the meter-reading previously predetermined in common with each meter terminal corresponding to the memory | storage content A terminal having a larger number of hops from the timing is provided with a communication control unit that speeds up the transmission timing of the meter-reading data.

  According to said structure, each said measuring device terminal utilizes the route hop number information which each hold | maintains in the memory | storage part, and a communication control part is based on the meter-reading timing previously predetermined in common with each measuring device terminal. Then, transmission of meter-reading data is started from the one with a large number of hops.

  Therefore, considering the occurrence of retransmission due to communication failure to the adjacent terminal (next hop) or the like and starting communication from a terminal far from the gateway, the collection reliability within the specified collection time can be increased.

  In the meter reading data collection system of the present invention, as described above, a number of measuring instrument terminals installed in each consumer constitute a network, and the meter reading data is set at predetermined time intervals or at the time when predetermined events occur. In a system that realizes automatic meter reading and the like by transmitting and collecting to the host device by multi-hop wireless communication, each meter terminal individually transmits the meter reading data, at least An aggregation terminal is provided in the wireless communication network, and the aggregation terminal collects the meter reading data for each packet size of the communication line on the host device side, and further distributes each other when a delay time preset in the aggregation terminal has elapsed. Then, transmission to the host device is started.

  Therefore, it is possible to suppress traffic near the host device, prevent data loss and communication errors due to complications, and collect meter reading data in a short time and with high reliability without increasing costs. can do.

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 the example of 1 structure of a gateway. 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 transmission procedure of the meter-reading data from the gateway to a server apparatus in the meter-reading data collection system which concerns on 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 gateway to a server apparatus in the meter-reading data collection system which concerns on other forms of implementation of this invention. It is a figure for demonstrating the transmission procedure of the meter-reading data from the gateway to a server apparatus in the meter-reading data collection system which concerns on the further another form of implementation of this invention.

(Embodiment 1)
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. , Which is indicated by the reference symbol U), dynamically, that is, always look around the surroundings, autonomously switch to the best route, configure a multi-hop wireless communication network, and read the meter reading data at predetermined time intervals or in advance. This is a system that realizes automatic meter reading by transmitting and collecting data to the server device 1 that is a host device at the time of occurrence of a predetermined event.

  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 symbols A1, A2, A3, and A4 in an ad hoc mode for wireless LAN terminal-to-terminal communication. When each measuring instrument terminal U is activated (turned on), it monitors the surrounding radio wave condition as described above, and the measuring instrument terminal having the best communication quality (hanging destination: measuring instrument terminal U1 in the example of FIG. 1). U2 for U3 and U4) for U3 to connect, that is, join the network, autonomously select the route to gateway 3 which is the end of the wireless communication network, and communicate in the ad hoc mode. Start.

  The gateway 3 connects a wireless communication network and a wired network 4 dedicated to a network operating company such as an electric power company. The server device 1 is connected to the wired network 4. This gateway 3 is provided in, for example, a main utility pole, and the number of accommodation terminals is several hundred. Further, the number of hops of each measuring instrument terminal U is several tens at the maximum, preferably 10 hops or less.

  In the meter reading data collection system configured as described above, it should be noted that in the present embodiment, the gateway 3 provided in the lower layer of the server device 1 receives meter reading data from each measuring instrument terminal U under its control. It functions as an aggregation terminal that aggregates and transmits to the server device 1. In the present embodiment, the aggregation terminal is the gateway 3 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. It may be provided in the middle of the multi-hop wireless communication network, or may be provided in a plurality of steps between the middle and the gateway 3. However, by using the gateway 3 at the boundary between wired and wireless as an aggregation terminal, the degree of parallelism between the aggregation terminals is high (the aggregation terminals are not scattered in different hierarchies), and the aggregation can be performed efficiently. it can.

  FIG. 2 is a block diagram showing a configuration example of the gateway 3. The gateway 3 communicates with the server device 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. A 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 A data processing unit 15 that aggregates each packet size of the wired network 4 (communication line) on one side, a work memory 16 that is used for the data processing, and an overall operation of the gateway 3 to control communication. And a clock unit 18 that holds time information serving as a reference for the operation of the control unit 17. That. 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 collected by the data processing unit 15 to the server device 1.

  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 instrument terminal U uses the CSMA / CA method to check the free state of the radio channel to be used, and as shown in FIG. 4, the hop number of the route to the gateway 3 is large. The transmission start timing is set so that the transmission starts as fast as the terminal.

  Therefore, each measuring instrument terminal U has a storage unit that stores the number of hops from the gateway 3 and a meter reading timing (for example, every hour) that is predetermined in advance for each measuring instrument terminal U corresponding to the stored contents. From 0 minutes and 30 minutes), a terminal having a larger number of hops is provided with a communication control unit that accelerates the timing of sending the meter-reading data. Thus, each measuring instrument terminal U utilizes the route hop count information held in the storage unit, and the communication control unit uses the predetermined meter reading timing common to each measuring instrument terminal U as a reference. By starting the transmission of meter-reading data from a large number of terminals, that is, terminals far from the gateway 3, even if a retransmission occurs due to a communication failure to an adjacent terminal (next hop), etc., within the specified collection time Collection reliability can be increased.

  On the other hand, the meter reading data transmitted from each measuring instrument terminal U arrives at the gateways A, B,..., X, is received by the interface 11, and is transmitted from the communication control unit 12 through the data processing unit 15. The data is sequentially stored in the work memory 16. For example, it takes 10 seconds to collect meter reading data from 500 measuring instrument terminals U, and 20 seconds is set as the first stage of these. 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 server device 1. Send sequentially. Thus, the collection of the collected meter reading data from tens of thousands of gateways 3 requires, for example, 180 seconds as the second stage. Thereafter, as a third stage, a predetermined idle time, for example, 100 seconds is secured, and the automatic collection of meter-reading data is completed in a total of 300 seconds.

  On the other hand, the controller 17 of each gateway 3 does not reach within the prescribed 20 seconds in the first stage, and discards the meter reading data that has arrived thereafter. For this reason, the server device 1 individually requests transmission of the non-delivery meter reading data after the idle time of the third stage to the measuring instrument terminal for which the meter reading data has not reached, and sends the request. A backup meter reading is performed in which the meter reading data is transmitted to the target measuring device terminal via a multi-hop communication path and the returned meter reading data is sequentially transferred to the server device 1.

  By the way, in the transmission of meter reading data from the gateway 3 to the server device 1, the communication control unit 14 collects the meter reading data in the server device 1 with high reliability in the wired network 4 used for the transmission. 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. 6A is a diagram illustrating a structure of a transmission packet in which meter-reading data transmitted from the gateway 3 to the server device 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. To this, 20 and 20 bytes of each of the IP and TCP headers are added, and the result is 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.

  It should be noted that in the present embodiment, as shown in FIG. 5, the control unit 17 starts from a reference time (the meter reading timing) t0 and delay times τ1, 1 set in advance in the respective gateways 3. This is to wait for τ2, τ3,... and start transmission of the aggregated packets to the server device 1. Specifically, each measuring instrument terminal U is given an ID number or an IP address given in advance as a unique value of a serial number. 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 The control 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, assuming that the number of accommodated data of one packet is 44 and the number of accommodated terminals of the gateway 3 is 500, each gateway 3 needs to transmit 12 packets of data for each meter reading, Is 15 seconds, the transmission time is 180 seconds. If the total number of terminals is 12 million, the number of gateways 3 is 24,000. If the number is distributed over the 15 seconds, the number of terminals is 0.625 msec. Therefore, since one gateway 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 server device 1 is 3000 PPS, it is possible to perform processing with a single device.

  By configuring in this way, each gateway 3 is simultaneously generated at each measuring instrument terminal U by measuring at a predetermined time or a predetermined period in each measuring instrument terminal U, and individually by multi-hop wireless communication. An enormous number of meter reading data to be transmitted is aggregated for each packet size of the wired communication line 4 on the server device 1 side, and distributed to each other when a delay time set in advance for each gateway 3 has elapsed. Since transmission to the server apparatus 1 is started, traffic near the server apparatus 1 can be suppressed, and data loss and communication abnormality due to complication can be prevented. In addition, since the control unit 17 adjusts the transmission timing of the aggregated meter reading data from the communication control unit 14 so as not to overlap, this also suppresses the complication of traffic in the vicinity of the server device 1. it can. In this way, meter reading data can be collected in a short time and with high reliability as a result, without cost increase.

  Further, in the present embodiment, the second communication unit 14 establishes a TCP session with the host device 1 for each predetermined period of timing shifted from each other between the measuring instrument terminals U. Since the meter reading data aggregated by the data processing unit 15 is transmitted one packet at a time, it is necessary to establish a TCP session for each packet, but each meter terminal U transmits meter reading data equally. In addition, it is possible to prevent a specific terminal from occupying a TCP session for a long time.

(Embodiment 2)
FIG. 7 is a diagram for explaining a procedure for transmitting meter reading data from the gateway 3 to the server device 1 in the meter reading data collecting system according to another embodiment of the present invention. The configuration of the meter reading data collection system according to the present embodiment is the same as that in FIGS. 1 and 2 described above, and the transmission method of the data collected by each gateway 3 to the server device 1 is only different from that in FIG. .

  First, the transmission packet from the gateway 3 to the server device 1 created from the meter reading data for 500 cases is 45 to 88 cases in (b) following the data for 44 cases in FIG. Min, (c) 89 to 132 cases (d) 485 to 500 cases. In the transmission method of FIG. 7, when 500 pieces of data are accumulated, the communication control unit 14 of the gateway 3 is activated, and a TCP session is created each time as shown in FIG. Will be sent. As shown in FIG. 7B, the procedure at that time is as follows. First, a synchronization request SYN is transmitted from the gateway 3 side, and in response to this, the server apparatus 1 transmits a synchronization signal SYN together with a permission signal ACK. When 3 returns a response signal ACK, synchronization (TCP session) is established between the gateway 3 and the server apparatus 1.

  Thereafter, the created 12 packet data are sequentially transmitted from the gateway 3 side, and the first packet, the middle packet and the last packet are determined by the server device 1 from the message type D01, and the reception of all packets is completed. The server apparatus 1 transmits a response signal ACK indicating that it has been received. In response to the response signal ACK, the gateway 3 transmits an end signal FIN indicating the end of the TCP session, and the server device 1 receives the end signal FIN in response to the end signal FIN. When the signal ACK is returned, the gateway 3 transmits a signal ACK indicating consent and the TCP session ends.

  In this way, in the aggregation terminal, that is, in the gateway 3 provided at the boundary between the wired and wireless, the second communication unit 13 that communicates with the host device 1 communicates with the wired network 4 using the TCP / IP protocol. When a TCP session is established, the TCP session is maintained (not disconnected) until all received meter reading data is transmitted to the host device 1, thereby reducing the number of TCP session establishments and completing the transmission in a shorter time. And the reliability of data can be improved.

  Also in the transmission method of FIG. 7, as shown in FIG. 5 described above, each gateway 3 may be provided with a different delay time to establish a TCP session.

(Embodiment 3)
FIG. 8 is a diagram for explaining a procedure for transmitting meter reading data from the gateway 3 to the server device 1 in a meter reading data collecting system according to still another embodiment of the present invention. The configuration of the meter-reading data collection system according to the present embodiment is the same as that shown in FIGS. 1 and 2, and the transmission method of the data collected by each gateway 3 to the server device 1 is only different from that in FIG. . It should be noted that in the transmission method according to the present embodiment, the second communication unit 13 always maintains a TCP session with the host device 1 as shown in FIG. ). Therefore, as shown in FIG. 8B, in the procedure at that time, there is no exchange of the synchronization signal SYN, and only the response signal ACK is transmitted from the server apparatus 1 after transmitting the data packet sequence. Thereby, the number of packets for establishing a TCP session can be reduced, and the total number of packets can be reduced.

  Table 1 shows the difference in the number of packets between the transmission method shown in FIG. 7 and FIG. 8, the method in which the conventional measuring instrument terminal directly transmits meter reading data to the server device, and the method in FIG. Show. Table 1 shows the results of trial calculations by the inventors of the present application. In Table 1, the aggregation method 1 corresponds to the transmission method of FIG. 5 and the aggregation method 2 corresponds to the transmission method of FIG. Aggregation method 3 corresponds to the transmission method of FIG. Therefore, the number of meter reading data per packet is 1 in the conventional method, and 44 in the methods 1 to 3 of the present invention as described above. Therefore, the packet size of the meter reading data is 1454 bytes as described above in the methods 1 to 3 of the present invention, whereas in the conventional method, the message type D01 and the number data D02 are unnecessary, and the meter reading data In 32 bytes, 20 bytes each of the IP header and TCP header are 72 bytes.

  The number of transmission / reception packets per sequence is 8 packets in the conventional method and the method 1 of the present invention, as can be understood from FIG. 7B, and in the methods 2 and 3 of the present invention, respectively, as shown in FIG. As apparent from (b) and FIG. 8 (b), 19 and 13 are obtained. Among them, the number of meter reading data packets is 1 in the conventional method and the method 1 of the present invention, and 12 as described above in the methods 2 and 3 of the present invention. Then, as described above, when the total number of terminals is 12 million and the number of accommodated terminals of each gateway 3 is 500, the number of gateways is 24000, and the total number of packets generated per meter reading with respect to the server device 1. Is 96 million for the conventional method and 23.04 million for the method 1 of the present invention, whereas it can be dramatically reduced to 456,000 and 312000 for the methods 2 and 3 of the present invention, respectively. As a result, when the total number of packets is distributed over the meter reading time of 180 seconds, the number of packets per second is 533334 in the conventional method and 12800 in the method 1 of the present invention, whereas the method 2 of the present invention. And 3 are 2534 and 1734, respectively.

  Here, when the processing capacity of the router interposed between the server device 1 and the wired network 4 is, for example, 1 Gbps, the data processing capacity with a packet size of 64 bytes is typically 1.48 million PPS at the maximum. The maximum data processing capacity of a packet size of 1482 bytes is 80,000 PPS. Further, when the processing capacity of the router becomes 100 Mbps, it becomes 1480,000 PPS and 8,000,000 PPS, respectively. Therefore, in the case of a router of 1 Gbps, any method can be supported. However, in the case of a router of 100 Mbps, the conventional method and the method 1 of the present invention cannot be supported, and the methods 2 and 3 of the present invention can be supported. It is understood that

  With this configuration, the communication control unit 14 of the gateway 3 once maintains the TCP session (does not disconnect) like the stream data once the TCP session is established for transmission of meter reading data. The number of TCP session establishments can be reduced, transmission can be completed in a shorter time, and data reliability can be improved.

  Further, as shown in FIG. 8, the second communication unit 14 maintains the TCP session with the host device 1 at all times (does not disconnect), thereby reducing the number of packets for establishing the TCP session. In addition, the total number of packets can be reduced. In addition, although explosive traffic occurs instantaneously at the timing of scheduled meter reading, there is no significant traffic within the meter reading network except during that time period, so even if TCP sessions are always connected, other meter readings are involved. There is no adverse effect on communication (communication for re-reading, remote control communication, etc.).

DESCRIPTION OF SYMBOLS 1 Server apparatus 3 Gateway 4 Wired network 11 Wireless LAN standard (IEEE802.11) interface 12, 14 Communication control part 13 Wired LAN standard (IEEE802.3) interface 15 Data processing part 16 Work memory 17 Control part A, B, ..., X Gateway H1, H2, ... Consumers U1, U2, ... Measuring instrument terminals U11 to U1m; U21 to U2n; Ux1 to Uxk Measuring instrument terminals

Claims (6)

A measuring instrument terminal installed in each consumer, a gateway connected to the measuring instrument terminal via a wireless communication network, and meter reading data is transmitted from each measuring instrument terminal in a multi-hop manner, and the gateway and a wired network A host device connected to each other, and an aggregation terminal provided in the wireless communication network,
The aggregation terminal is:
A first communication unit for receiving meter reading data individually 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 terminal has elapsed from a reference time Collection system. Each weighing terminal performs communication according to the wireless LAN standard,
2. The meter reading data collection system according to claim 1, wherein the aggregation terminal includes the gateway interposed between a wireless LAN line on the measuring instrument terminal side and a wired LAN line on the host device side.   In the gateway, the second communication unit communicates the wired LAN line with the host device using a TCP / IP protocol, and the second communication unit transmits a TCP session with the host device. 3 is established for each predetermined period of timing shifted from each other between each measuring instrument terminal, and meter reading data aggregated by the data processing unit is transmitted one packet at a time for each period. The meter reading data collection system described.   In the gateway, the second communication unit communicates the wired LAN line with the host device using a TCP / IP protocol, and establishes a TCP session after the gateway is activated. 3. The meter-reading data collection system according to claim 2, wherein the TCP session is maintained until all of the above are transmitted to the host device.   The meter-reading data collection system according to claim 4, wherein the second communication unit constantly maintains a TCP session with the host device.   Each meter terminal is a storage unit that stores the number of hops from the gateway, and a meter reading timing that is predetermined in advance for each meter terminal in correspondence with the stored content, so that the terminal having a larger number of hops, The meter-reading data collection system of any one of Claims 1-4 provided with the communication control part which speeds up the transmission timing of the meter-reading data.

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