WO2012101779A1 - Network management system, network management server, network terminal, and network management method - Google Patents

Abstract

Provided are: a network management system able to support a simultaneous distribution that is a request from an automatic meter reading system and that is from a gateway to a terminal; a network management server; a network terminal; and a network management method. The network management server is provided with: a recording unit that records a slot table containing a first communication period, which indicates a period of communication among a plurality of network terminals and a network management server by means of a first communication method, and a second communication period, which indicates a period of communication of the plurality of network terminals and the network management server by means of a second communication method that differs from the first communication method; a synchronization time management unit that externally acquires time synchronization information for synchronizing the time among the plurality of network terminals; and a server wireless control unit that transmits the time synchronization information and the slot table to the plurality of network terminals, and on the basis of the first communication period and the second communication period contained in the slot table and the time synchronization information acquired by the synchronization time management unit, switches the communication method among the plurality of network terminals and the network management server to either the first communication method or the second communication method. Each of the plurality of network terminals is provided with: a time management unit that, on the basis of the time synchronization information, causes the time of the network terminal to be synchronized to a predetermined time; and a terminal wireless control unit that receives the slot table and the time synchronization information from the network management server, and in accordance with the first communication period and second communication period contained in the slot table and the time synchronized by the time management unit, communicates among the plurality of network terminals and the network management server by means of the first communication method or second communication method that has been switched to.

Description

Network management system, network management server, network terminal, and network management method

The present invention relates to a network management system, a network management server, a network terminal, and a network management method for switching radio systems of all terminals existing in a network in a time division manner in order to satisfy a communication form required by the system.

In recent years, there is a movement to automate the meter reading work of electricity, gas, water, etc. by using wireless communication such as wireless LAN (Local Area Network) and specific low power wireless. By automating the meter reading work, it becomes possible to reduce the meter reading work cost and grasp the usage status of electricity, gas and water in real time.

An automatic meter reading system using wireless communication (hereinafter referred to as an automatic meter reading system) is a system that connects hundreds to tens of thousands of meter reading terminals via a wireless network. However, wireless communication such as wireless LAN and specific low power wireless is limited to the radio wave reach. Therefore, it is common to use multi-hop communication in order to enable data communication of all terminals existing in the network. Multi-hop communication enables data communication between terminals by transferring data to a terminal located between the two terminals, even when the two terminals performing data communication do not exist within the communication range of each other Communication. However, in multi-hop communication, when the number of transfers (hereinafter referred to as the number of hops) increases, there is a problem that the data arrival rate to the terminal decreases.

The automatic meter reading system requires a collection of meter reading data from all terminals in the network within a certain period of time and a request to reliably distribute the same data to all terminals in order to update software and send time synchronization information. There is. The former requires high-speed data communication due to the restriction of a certain time. The latter requires data communication with a small number of hops, that is, a wide communication range, due to certainty restrictions. However, in general, wireless communication has a characteristic that high-speed communication has a narrow communication range, and low-speed communication has a characteristic that the communication range is wide. Therefore, the two requirements of the automatic meter reading system cannot be satisfied at the same time. Therefore, a mechanism for efficiently switching between wireless systems having different characteristics has become necessary.

Patent Document 1 has been proposed as a technology for efficiently switching between two wireless systems. Patent Document 1 is a technique for switching a wireless system according to a terminal state such as a moving speed or a user selection. Specifically, when the terminal is moving at a high speed, in order to reduce the frequency of communication disconnection with the gateway, a low-speed wireless method with a wide communication range is selected, and conversely, when the terminal is moving at a low speed, the gateway This is a technology that has a feature of selecting a wireless system with a high communication speed and a narrow communication range.

JP 2004-208001 A

The technology of Patent Document 1 switches the wireless method depending on the state of the terminal such as the moving speed. For this reason, when the terminals existing in the network are different from each other, the wireless method selected by each terminal is also different, and therefore, it is not possible to perform simultaneous data distribution as a requirement of the automatic meter reading system.

Furthermore, in a state where the moving speed changes frequently, the wireless system of the terminal also changes frequently, so there is a possibility that a large load is applied to the terminal.

In order to solve the above problems, the present invention performs time synchronization for all terminals in an automatic meter reading system, and unifies the time zone in which the two radio systems are used in the system, thereby providing a system at a certain time. It is an object of the present invention to provide a network management system, a network management server, a network terminal, and a network management method capable of determining a wireless system used in the network.

In order to solve the above-described problems and achieve the object, a network management system according to the present invention includes a plurality of network terminals capable of communicating by a plurality of wireless systems, and network management for managing communication between the plurality of network terminals. A network management system connected to a server via a network, wherein the network management server indicates a period during which communication is performed between the network management server and the plurality of network terminals by a first communication method. A storage unit for storing a slot table including a period and a second communication period indicating a period in which communication is performed in the network management server and the plurality of network terminals by a second communication method different from the first communication method; The time between the plurality of network terminals A synchronization time management unit for acquiring time synchronization information for externally transmitting the time synchronization information and the slot table to the plurality of network terminals, and the time synchronization information acquired by the synchronization time management unit and the Based on the first communication period and the second communication period included in the slot table, a communication method between the network management server and the plurality of network terminals is set to the first communication method or the second communication method. A server radio control unit that switches to any one of the communication methods, each of the plurality of network terminals, based on the time synchronization information, a time management unit that synchronizes the time of the network terminal to a predetermined time, Receiving the time synchronization information and the slot table from the network management server; The network management server according to the first communication method or the second communication method switched according to the synchronized time and the first communication period and the second communication period included in the slot table. A terminal radio control unit that communicates between the plurality of network terminals.

The present invention also provides a network management method, a network management server, and a network terminal that are executed by the network management system.

By using the present invention, since the wireless system used in the system is unified, it is possible to support simultaneous delivery from the gateway to the terminal, which is a request of the automatic meter reading system.

Schematic diagram of automatic meter reading system during data collection Schematic diagram of automatic meter reading system for simultaneous data distribution Schematic diagram of terminal GW device configuration Schematic diagram of GW functional configuration Schematic diagram of terminal function configuration Schematic of time frame Schematic diagram of various tables Schematic diagram of GW power-on flowchart Schematic diagram of terminal power-on flowchart Schematic diagram of GW time slot information transmission flowchart Schematic diagram of data relay transfer flowchart Time synchronization sequence diagram Data collection sequence diagram Data distribution sequence diagram Sequence diagram of data retransmission processing Schematic of time slot change flowchart Advance notification method sequence diagram

(First embodiment)
FIG.1 and FIG.2 is the schematic of the automatic meter-reading system which is 1st embodiment of this invention. The automatic meter reading system includes a terminal 300 that performs meter readings such as electricity and water, management and control of the terminal 300, a gateway (GW) 200 that collects data from the terminal 300, and a server 100 that collects meter reading data collected by the GW 200. It consists of In the example shown in FIG. 1, a plurality of terminals are connected to the GW 200, but in the following, these terminals are representatively described as the terminal 300.

FIG. 1 is a diagram showing an outline of a system at the time of data collection in which each terminal transmits meter reading data to the GW 200. Data collection needs to be performed by high-speed data communication because each terminal needs to perform data transmission within a certain period of time. When performing high-speed data communication, the communication range becomes narrow. For example, when the terminal 370 transmits meter reading data to the GW 200, the data transmitted by the terminal 370 is transmitted to the terminal 360 and the terminal 350, respectively. The system configuration is such that the data is transmitted to the GW 200. In the following, the communication method when data communication is performed with the system configuration of FIG. 1 will be referred to as a speed priority method.

FIG. 2 is a diagram showing an outline of a system at the time of simultaneous distribution in which the GW 200 transmits data for time synchronization to the terminals all at once. The simultaneous delivery needs to be performed by data communication with a small number of hops, that is, a wide communication range, because each terminal needs to reliably receive the data transmitted by the GW 200. For example, when the GW 200 transmits data, the terminal 300 and the terminal 350 receive the data, and only the terminal 350 receives the data by the transferred data. In the following, the communication method when data communication is performed with the system configuration of FIG. 2 will be referred to as a distance priority method.

FIG. 3 shows a device configuration diagram of the GW 200 and the terminal 300 in the automatic meter reading system. The GW 200 includes a central processing unit (CPU) 210, a volatile memory 212, a storage device 214, a timer 216, a wired communication IF 218, and a wireless communication IF 220. The storage device 214 stores meter reading data collected from each terminal, data for simultaneous distribution to each terminal, and various data used for storing a route table necessary for communicating with each terminal. . The timer 216 is used for processing such as switching between the speed priority method and the distance priority method. The wired communication IF 218 is an interface that performs data communication with the server 100, and corresponds to Ethernet (registered trademark), PLC (Power Line Communication), and the like. Note that a wireless interface such as a mobile network or WiMAX (registered trademark) may be used as an interface for performing data communication with the server 100. The wireless communication IF 200 is an interface that performs data communication with the terminal 300, and corresponds to a wireless LAN, a specific low power wireless, or the like.

The terminal 300 includes a CPU 310, a volatile memory 312, a storage device 314, a timer 316, a data acquisition unit 318, and a wireless communication IF 320. The storage device 314 stores meter reading data acquired by the terminal 300 and various data used for storing a route table necessary for communicating with the GW 200. The timer 316 is used for processing such as switching between the speed priority method and the distance priority method. The data acquisition unit 318 is used for collecting meter reading data and controlling the meter from meters such as electricity, gas, and water connected to the terminal 300. The wireless communication IF 320 is an interface that performs data communication with the GW 200, and corresponds to a wireless LAN, a specific low power wireless, or the like.

FIG. 4 is a schematic diagram of a functional configuration of the GW 200. The synchronization time management function 430 is a function that manages and controls the time synchronization of each terminal managed by the GW 200 and the data transmission timing of each terminal, and includes a synchronization time acquisition function 432 and a time slot management function 434. . The synchronization time acquisition function 432 is a function for acquiring the time managed by the server 100 using NTP (Network Time Protocol) or the like. The time slot management function 434 is a function for determining the data transmission timing of each terminal managed by the GW 200. As will be described later, the time acquired in this way is distributed to each terminal, the time between the GW 200 and each terminal 300 is synchronized, the time is the starting point, and each terminal 300 is transmitted from the GW server 200. Referring to the data transmission timing 728 included in the time slot table, each terminal 300 sequentially receives data from the GW 200 for the period indicated by the slot interval 640 assigned to each terminal 300, or a GW server 200 is transmitting data.

The path information generation function 440 is a function for constructing a transmission path necessary for performing data communication between the GW 200 and the terminal. This function uses a transmission path construction technique generally used in wireless multi-hop communication.

For example, Non-Patent Literature 1 (C. PERKINS), AD HOC ON-DEMAND DISTANCE VECTOR (AODV) ROUTING, RFC3561, HTTP: //WWW.IETF.ORG/RFC/RFC3561.TXT, July 2003), a terminal that transmits data broadcasts a route request message, searches for a data receiving terminal, and the data receiving terminal transmits a route response message in the reverse order of the route that received the route request message. Is returned to the data transmission terminal. In this way, the terminal that has received and transferred the route response message holds the transferred information as route information, thereby constructing a transmission route.

Other examples include Non-Patent Document 2 (T. CLAUSEN, OPTIMIZED LINK STATE ROUTING PROTOCOL (OLSR), RFC 3626, HTTP: //WWW.IETF.ORG/RFC/RFC3626.TXT, IETF, As described in August, 2003), all the terminal information in the system is grasped by transmitting the terminal search message periodically. When data transfer is performed, a transmission path is constructed by determining the transfer destination using the neighboring terminal information of its own terminal.

The time management function 450 is a function for making a state transition of the GW 200 using the timer 216 with reference to a time slot table 486 described below. The transmission data generation / reception data analysis function 460 is a function for creating data to be transmitted and analyzing the received data.

The communication function 470 is a function for data communication with each terminal, and includes a wireless control function 472. The wireless control function 472 is a function that changes transmission power and modulation method according to the speed priority method and the distance priority method. In addition to changing the transmission power and modulation method, a method of switching between the speed priority method and the distance priority method by mounting two different wireless devices may be used. However, switching the transmission power and modulation method is more effective in terms of cost and power consumption.

The data collection function 410 is a function of collecting data from the terminal 300 and storing it in the storage device 214. The server communication function 420 is a function for acquiring information necessary for time synchronization and transmitting meter reading data collected from each terminal.

The storage device 214 includes collected data 480 collected from the terminal 300, a route table 482 created by the route information generation function 440, a time slot management table 484 that is time slot information of all terminals, and a time slot that is its own time slot information. The table 486 is saved. Details of each table will be described below.

FIG. 5 shows a functional configuration diagram of the terminal 300. The time management function 510 is a function for making a state transition of the terminal 300 using the timer 316 with reference to a time slot table 486 described below. The time management function 510 is a function that corrects the time based on information related to time synchronization periodically transmitted by the GW 200.

The route information generation function 520 is a function for constructing a transmission route necessary for data communication between the GW 200 and each terminal. Note that the route information generation method is the same as that of the GW 200, and thus the description thereof is omitted. The transmission data generation / reception data analysis function 530 is a function for generating data to be transmitted and analyzing the received data.

The data acquisition unit control function 540 controls the operation of the data acquisition unit 318. The communication function 550 is a function for data communication with the GW 200, and includes a wireless control function 552. The wireless control function 552 is a function that changes transmission power and modulation method according to the speed priority method and the distance priority method.

The storage device 214 includes acquisition data 560 such as meter reading data acquired from the data acquisition unit 318, a terminal unique number 564 uniquely assigned to each terminal 300, a route table 482 created by the route information generation function 520, and its own time. A time slot table 486 which is slot information is accumulated. Details of each table will be described below.

Here, when describing the embodiment, the components of the present embodiment will be described in terms of “function”, but each “function” indicates a logical configuration and is implemented in a physical configuration. Or a function implemented by an information processing program.

FIG. 6 is a diagram showing a schematic diagram of the time frame 610. The time frame 610 is a unit of one time interval set in advance by an administrator or the like. As shown in FIG. 6, the time frame 610 includes a distance priority period 620 in which communication is performed using a distance priority method and a speed priority period 630 in which communication is performed using a speed priority method.

Furthermore, the speed priority period 630 provides a slot interval 640 for each terminal, which is a period during which each terminal 300 can transmit data to the GW 200. FIG. 6 shows a case where a total of n slot intervals 640 of C1 to Cn are provided, assuming that the number of terminals is n. In this description, the distance priority period is a period during which the GW 200 broadcasts to each terminal. However, the distance priority period may include a period during which each terminal broadcasts. However, in this case, it is necessary to set a period during which each terminal can perform broadcast transmission, similar to the speed priority period. Further, a configuration in which the distance priority period is used for unicast communication or multicast communication instead of broadcast transmission may be used.

FIG. 7 is a schematic diagram of various tables. The time slot management table 484 is managed by the GW 200 and includes a terminal unique number 566, an IP address 712 that is a terminal address, and an acquisition data transmission timing 714. The unique number 566 and the IP address 712 of each terminal are determined in advance. For example, the time slot management function 434 acquires these pieces of information from the server 100 and acquires data transmission timing which is the data transmission order from the GW 200 to the terminals. 714 is determined.

The time slot table 474 includes a time frame 610, a speed priority period 620, a distance priority period 630, a slot interval 640, and an acquisition data transmission timing 728. In the time slot table 474, the time slot management function 434 of the GW 200 creates the slot interval 640 from the speed priority period and the number of terminals from the time slot management table 472, and the server communication function 420 generates the slot interval 640. The time slot table 474 is distributed to all the registered terminals 300. In this embodiment, the speed priority period 620 and the distance priority period 630 are described as time intervals (seconds). For example, the interval (period) is determined by setting the start time and the end time. Also good.

The route table 562 includes a destination IP address 730 and a transfer destination IP address 732. The route table 562 is created by the route information generation function 440 of the GW 200 and the route information generation function 520 of the terminal 300. The route table 562 can be created by applying a route information construction method generally used in wireless multi-hop communication. When the GW 200 or the terminal 300 receives data and the destination IP address in the data is different from its own IP address, the data is transferred to the transfer destination IP address 732 according to the destination IP address in the data.

In addition, when the destination IP address 730 is a broadcast address, the presence / absence of transfer is confirmed and re-broadcast is determined. The route table 562 is created using the transmission route construction technology of Non-Patent Document 1 and Non-Patent Document 2. Further, since the communicable range is different between the speed priority method and the distance priority method, and the terminal 300 to which the data is transferred is also different, the route table 562 is created by each method.

FIG. 8 shows a schematic diagram of a flowchart when the GW 200 is turned on. When the power of the GW 200 is turned on by an administrator or the like (step 800), the route information generation function 440 of the GW 200 creates a route table 482 using the techniques described in Non-Patent Document 1 and Non-Patent Document 2. (Step 810), a route table 482 generation process is performed.

The time slot management function 434 refers to the time slot management table 472 of the GW 200 and assigns the time slot table 474 to each terminal 300 (step 820). The allocation of the time slot table 474 will be described later. The GW 200 executes the subsequent processing until the power is turned off. When the power is turned off, the GW 200 ends the processing shown in FIG. 8 (step 821).

In the process related to the allocation of the time slot table 474 described later, the time slot table 474 is broadcast to each terminal 300 for each terminal 300, but even in this case, these times are also broadcast. The slot table 474 is generated by copying from the original time slot table 474 (a combination of the time slot tables 474 of each terminal 300) and is stored in the storage device 214 of the GW 200.

Next, the time management function 450 periodically inquires of the presence or absence of an interrupt by the built-in timer 216 (step 822). This interruption is for confirming whether or not each terminal 300 has received the time slot table 474. When each terminal 300 receives the time slot table 474 transmitted from the GW 200, the interruption is transmitted from each terminal 300. Generated by the generated signal. When an interrupt occurs, the time management function 450 refers to the time slot table 474 and confirms whether it is the time zone of the distance priority period 620 or the speed priority period 630 (step 824). If it is the distance priority period 620, the wireless control function 472 sets the wireless method to the distance priority method (step 826), for example, when simultaneously distributing data for upgrading the software of all terminals, The server communication function 420 performs the simultaneous distribution process (step 830) and returns to the presence or absence of the timer interruption (step 822).

On the other hand, when the time slot table 474 is confirmed (step 824), if the speed priority period 630, the wireless control function 472 changes the communication method to the speed priority method (step 832). Next, the time slot management function 434 determines whether it is the acquisition data transmission timing of the time slot table 474 (step 834), and if it is the acquisition data transmission timing, the data collection function 410 is, for example, all terminals A data collection process (step 840) for collecting meter reading data measured by each of the server communication function 420 is performed. Otherwise, the server communication function 420 executes software for a terminal designated in advance by an administrator or the like. Data distribution processing (step 850) for distributing data for upgrading is performed. The distribution processing in step 850 is performed, for example, when data cannot be distributed due to some circumstances at the time of simultaneous distribution, or to give an instruction only to a specific terminal. The above processing is repeated by the timer 216.

Subsequently, FIG. 9 shows a schematic diagram of a flowchart when the terminal 300 is turned on. When the terminal 300 is powered on by an administrator or the like (step 900), the route information generation function 520 creates a route table 482 (step 810), and the time slot table 474 assigned by the GW 200 via the server 100. Is received (step 820). The terminal 300 executes the subsequent processing until the power is turned off. When the power is turned off, the terminal 300 ends the processing shown in FIG. 9 (step 921).

Next, the time management function 510 uses the built-in timer 316 to inquire about the presence or absence of an interrupt, and transmits a signal to that effect to the GW 200 (step 922). When the timer interrupt occurs, the time management function 510 checks its own time slot table 474 to check whether it is the distance priority period 620 or the speed priority period 630 (step 924). If it is the distance priority period 620, the wireless control function 552 sets the communication method to the distance priority method (step 926), for example, performs a simultaneous distribution process of the meter reading data acquired by the data acquisition unit 318 (step 830), The process returns to the timer interrupt (step 922). When the processing in step 830 is performed, data (for example, meter reading data) is transmitted from the terminals to the GW 200 simultaneously by the distance priority method.

On the other hand, when the time management function 510 confirms the time slot table 474 (step 924), if it is the speed priority period 630, the radio control function 552 sets the radio system to the speed priority system (step 932). Next, it is confirmed whether or not its own terminal 300 is in the time interval of the slot interval 640 in the time slot table 474 (step 934). If so, the wireless control function 552, for example, reads the meter reading acquired by the data acquisition unit 318. Data distribution processing for transmitting data to the GW 200 is performed (step 850). Otherwise, the data acquisition unit 318 performs data collection processing (step 840) for collecting meter reading data, for example. The above processing is repeated by the timer 316. When the processing of step 850 is performed, each terminal sequentially transmits a time slot table 486 to the GW 200 at a predetermined timing (acquired data transmission timing 728 of the time slot table 486 set for each terminal). The above-described meter reading data and the like are transmitted at the time designated by the slot interval 640.

FIG. 10 shows a schematic diagram of a flowchart of time slot allocation processing in the GW 200. In the GW 200, the time slot management function 434 inquires of the server 100 about the number of terminals under the GW 200 (step 1002). Next, the time slot management function 434 creates a time slot management table 484 from the number of terminals (step 1004). The acquisition data transmission timing 714 of the time slot management table 484 is set in ascending / descending order from the terminal unique number 564 and the IP address. Then, the time slot management function 434 sets the slot interval from the number of terminals registered in the created time slot management table 472 and the speed priority period, and the server communication function 420 is a terminal in which the time slot table 486 is registered. It transmits to all by broadcast (step 1008).

Fig. 11 shows a sequence diagram of the time slot allocation process. In the GW 200, the time slot management function 434 generates transmission data of the time slot table 472 from the time slot management table 472 (step 1202). At that time, the terminals 300, 302, and 304 for which the route table 482 generation processing by the route information generation function 440 has ended are waiting for data reception.

Next, in the GW 200, the server communication function 420 performs data transmission (step 1204), and in the terminal 300, the communication function 550 receives the data (step 1206). The received data is subjected to reception data processing by the transmission data generation / reception data analysis function 530 (step 1100), and the time management function 510 performs time synchronization processing (step 1214), and the processing ends. In addition, when the transmission data generation / reception data analysis function 530 performs reception data processing (step 1100), the terminal 300 determines whether or not the route information generation function 520 requires relay transfer, and the communication function 550 Data is relayed and transferred.

In the terminal 304 that has received the data (step 1212), the transmission data generation / reception data analysis function 530 performs reception data processing (step 1100), and the time management function 510 performs time synchronization processing (step 1222). finish. If the terminal 302 fails to receive data (step 1206), the terminal 302 remains in a data reception waiting state until the next time slot table 474 is transmitted. Note that the GW 200 and all the terminals 300 set either the speed priority method or the distance priority method as an initial state from when the power is turned on until the time slot table is received.

FIG. 12 shows a schematic diagram of a flowchart of received data processing. In each terminal 300, the communication function 550 receives data (step 1102), and the transmission data generation / reception data analysis function 530 determines whether the destination added to the received data is addressed to its own terminal 300. (Step 1104). If it is addressed to itself, as shown in FIG. 9, processing corresponding to the received data is performed (step 1106).

On the other hand, when the transmission data generation / reception data analysis function 530 determines that it is not addressed to itself, the path information generation function 520 refers to the path table 482 (step 1108) and adds the transfer destination IP address 732 to the data. The data received by the communication function 550 is transferred (step 1112). Also, when the destination added to the data is a broadcast address, the transmission data generation / reception data analysis function 530 refers to the transfer destination IP address, and if there is a transfer, re-broadcasts the received data as it is ( Step 1112). The route information generation function 520 determines whether or not transfer or broadcast is necessary. If there is no need for transfer or broadcast, the received data is discarded. Transfer is performed (step 1112).

Fig. 13 shows a sequence diagram of the data collection process. The GW 200 is in a state of waiting for data reception. Since the terminal 300 confirms the time frame 610 and is its own transmission timing 714, the transmission data generation / reception data analysis function 530 generates transmission data (step 1302). On the other hand, since the terminals 302 and 305 are not at the transmission timing 714, they are waiting for data reception. The terminal 300 that created the transmission data transmits data to the GW 200 by the communication function 550 (step 1304), and waits for data reception. Here, since the data transmission has failed (step 1306), the retransmission process is repeatedly performed at a predetermined timing during the slot interval 640 of the time slot table 474.

Next, the terminal 305 receives the transmission timing 714 (step 1310), generates transmission data similarly to the terminal 300 (step 1310), and performs data transmission (step 1314). The terminal 302 receives the transmission data (step 1316). In the terminal 302, the transmission data generation / reception data analysis function 530 performs reception data processing (step 1110), and the destination in the data is GW200. Therefore, the communication function 550 performs relay transfer by adding the GW 200 of the transfer destination IP address in the route table 562 to the received data (step 1320).

The GW 200 receives the transmission data (step 1320), the transmission data generation / reception data analysis function 460 performs reception data processing (step 1330), and stores the transmission data (ie, collected data) in the storage device 214. (Step 1332), and the process ends. Note that data collected from the terminal 300 is periodically transmitted to the server 100 by the server communication function 420 of the GW 200.

FIG. 14 shows a schematic diagram of a sequence diagram of data distribution processing. In the GW 200, the time slot management function 434 refers to the time slot table 474, and the transmission data generation / reception data analysis function 460 performs transmission data generation because of the transmission timing (step 1402), and the communication function 470 Transmission is performed (step 1404). Here, since data transmission has failed (step 1406), retransmission processing is performed.

Next, the communication function 470 performs data retransmission processing (step 1500) and performs data retransmission (step 1408). In the terminal 300 that has received the data, the transmission data generation / reception data analysis function 530 performs reception data processing (step 1100), transfers to the terminal 302 in the same manner as shown in FIG. 13, and waits for data reception. In the terminal 302 that has received the data, the transmission data generation / reception data analysis function 530 performs reception data processing (step 1100), and transmits the response transmission to the GW 200 (step 1422).

When the terminal 300 receives the data (step 1424), the received data processing (step 1100) is performed and transferred as in the case shown in FIG. The GW 200 that has received the data can confirm that the transmitted data has reached the terminal 302 by receiving the response.

FIG. 15 shows a flowchart of data retransmission processing. When the GW 200 or the terminal 300 transmits data, it enters a data reception waiting state. The communication function 550 and the communication function 470 wait for reception of a response for a predetermined time (step 1502). If a response is received, the data has arrived and the process is terminated.

On the other hand, when the response cannot be received, the communication function 550 and the communication function 470 check the number of retransmissions in the time slot (step 1504), and if smaller than the predetermined number, perform the retransmission (step 1506). If it is equal to or greater than a certain number of times, the processing is terminated if it is smaller than the total number of retransmissions, and if it is larger, the route information generation function 440 and the route information generation function 520 reconstruct the transmission route and reconstruct the route table 482. Perform (step 1510). Through the above processing, all terminals in the meter-reading system and the GW 200 can cope with simultaneous delivery by switching the wireless system in the time zone.

FIG. 16 is a diagram showing a schematic diagram of a change flowchart of the time frame 610. In an automatic meter reading system, a terminal is normally added or deleted, but if a terminal is added, there is a possibility that the acquired data transmission timing 728 cannot be assigned to the added terminal due to a lack of speed priority period. There is. Moreover, when the data for simultaneous delivery is large, it is required to extend the distance priority period. Therefore, it is necessary to change the distance priority period and the speed priority period.

When changing the time frame 610, the GW 200 confirms from the time slot management table 472 whether the time slot management function 434 has a time zone in which the slot interval 640 is not allocated in the time zone of the speed priority period 630 ( Step 1602). If there is a vacancy, the time slot management function 434 recreates the time slot management table 472 (step 1604).

Then, if there is a terminal that needs time slot allocation change, the time slot management function 434 requests the necessary terminal to change the time slot allocation (step 1608). The table 474 is transmitted (step 1610).

On the other hand, when there is no free space in the speed priority period 630 (step 1602), the time slot management function 434 changes the slot interval 640 from the number of managed terminals (step 1612) and recreates the time slot management table. After that (step 1614), the re-created time slot table 474 is transmitted (step 1610).
(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the present embodiment, the wireless method is switched according to the time zone. For this reason, data collection and simultaneous transmission cannot be performed until a time period when switching to a wireless system according to a request. Therefore, a technique of a prior notification method for switching by explicitly instructing a wireless method will be described. Note that the prior notification method is set to the speed priority method in the normal state for both the GW 200 and the terminal 300.

Fig. 17 shows a sequence diagram of the prior notification method. As shown in FIG. 17, when the GW 200 receives a simultaneous delivery request, the radio control function 472 creates data for notifying the communication method change (step 1702). Next, the communication function 470 transmits the created data (step 1702) and waits for a response from the terminal. Here, since the data transmission has failed, a data retransmission process (step 1500) is performed, and the GW 200 waits for a response.

When the terminal 300 receives data from the GW 200, the transmission data generation / reception data analysis function 530 performs reception data processing (step 1100), and the time management function 510 starts its timer 316 (step 1712), A response transmission is transmitted to the GW 200 (step 1714), and data reception is awaited.

In the GW 200 that has received the response transmission, the transmission data generation / reception data analysis function 460 performs reception data processing (step 1100), and the communication function 470 transmits data to the terminal 302 (step 1706).

When the terminal 300 receives data, the transmission data generation / reception data analysis function 530 performs reception data processing (step 1100), the communication function 550 transfers data, and waits for data reception. When the terminal 302 receives the data, the received data processing is performed in the same manner as the terminal 300 (step 1100), the time management function 510 starts its own timer 316 (step 1722), and transmits a response to the GW 200 (step). 1724).

The terminal 300 that has received the response transmission performs reception data processing in the same manner as in Step 1100 (Step 1100), transfers data to the GW 200, and when the GW 200 receives data, the received data is received in the same manner as in Step 1100. Processing is performed (step 1100). As a result, the GW 200 can recognize that each terminal has been able to appropriately set the radio system. Such processing is performed for all terminals in the automatic meter reading system, and each terminal sets the communication method to the distance priority method when the time set by the timer 316 is reached. That is, the time management function 510 of each terminal changes the communication method at the same timing according to each terminal (for example, distance, network hierarchy, etc.) of the timer start time of each terminal. Can do.

Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

100 Server 102 Speed priority method 103 Distance priority method 200 Gateway (GW)
210 CPU
212 Volatile memory 214 Storage device 216 Timer 218 Wired communication IF
220 Wireless communication IF
300 terminal 310 CPU
312 Volatile memory 314 Storage device 316 Timer 318 Data acquisition unit 320 Wireless communication IF
410 Data collection function 420 Server communication function 430 Synchronization time management function 432 Synchronization time acquisition function 434 Time slot management function 440 Route information generation function 450 Time management function 460 Transmission data generation / reception data analysis function 470 Communication function 472 Radio control function 480 Collection Data 482 Route table 484 Time slot management table 486 Time slot table 510 Time management function 520 Route information generation function 530 Transmission data generation / reception data analysis function 540 Data acquisition unit control function 550 Communication function 552 Radio control function 560 Acquisition data 564 Terminal-specific Number 610 Time frame 620 Distance priority period 630 Speed priority period 640 Slot interval 712 IP address 714 Acquisition data transmission timing 728 Acquisition data transmission timing 730 Previous IP address 732 destination IP address.

Claims (13)

A network management system in which a plurality of network terminals capable of communicating by a plurality of wireless systems and a network management server that manages communication between the plurality of network terminals are connected via a network,
The network management server
A first communication period indicating a period of communication between the network management server and the plurality of network terminals by a first communication method; and a second communication method different from the first communication method, and the network management server and A storage unit for storing a slot table including a second communication period indicating a period of communication in the plurality of network terminals;
A synchronization time management unit for acquiring time synchronization information for synchronizing the time between the plurality of network terminals from the outside;
The time synchronization information and the slot table are transmitted to the plurality of network terminals, the time synchronization information acquired by the synchronization time management unit, and the first communication period and the second communication included in the slot table. A server radio control unit that switches a communication method between the network management server and the plurality of network terminals to either the first communication method or the second communication method based on a period,
Each of the plurality of network terminals is
A time management unit that synchronizes the time of the network terminal with a predetermined time based on the time synchronization information;
The time synchronization information and the slot table are received from the network management server, according to the time synchronized by the time management unit and the first communication period and the second communication period included in the slot table. A terminal radio control unit that communicates between the network management server and the plurality of network terminals by the switched first communication method or the second communication method;
A network management system characterized by comprising: The server radio control unit switches between the first communication method and the second communication method by changing a transmission power or a modulation method.
The network management system according to claim 1. The slot table further includes a transmission timing of predetermined data transmitted by the first communication method or the second communication method for each of the plurality of network terminals,
In the network management server, the synchronization time management unit determines the transmission timing of the predetermined data based on the slot table.
The network management system according to claim 1, wherein the system is a network management system. Each of the plurality of network terminals, the terminal radio control unit transmits the predetermined data to the network management server based on the transmission timing of the slot table received from the network management server,
The network management system according to claim 3. The first communication period or the second communication period included in the slot table and the transmission timing can be arbitrarily changed.
The network management system according to claim 3 or 4, wherein The first communication method or the second communication method is a speed priority method in which a communication range is determined by speed or a distance priority method in which the communication range is determined by distance.
The network management system according to any one of claims 1 to 5, wherein: The network management server transmits the predetermined data to the whole of the first communication period or the second communication period and to each of the plurality of network terminals when the communication method is the speed priority method. A slot table management unit for changing the transmission timing based on the total of the transmission timings for
The network management system according to claim 6, further comprising: For each of the plurality of network terminals, the terminal radio control unit, the network management server sets the communication method between the network management server and the plurality of network terminals, the first communication method or the second communication method. Switch the communication method on the network terminal side according to any of the
The network management system according to any one of claims 1 to 7, characterized in that: A network management method performed in a network management system in which a plurality of network terminals capable of communicating by a plurality of wireless systems and a network management server that manages communication between the plurality of network terminals are connected via a network,
A synchronization time management step of acquiring time synchronization information for synchronizing time between the plurality of network terminals from the outside;
A first communication period indicating a period of communication between the network management server and the plurality of network terminals according to the time synchronization information and the first communication method; and a second communication method different from the first communication method. A slot table including a second communication period indicating a period of communication between the network management server and the plurality of network terminals, and the time synchronization information acquired by the synchronization time management unit. Based on the first communication period and the second communication period included in the slot table, a communication method between the network management server and the plurality of network terminals is set to the first communication method or the second communication method. A server radio control step for switching to any one of the communication methods;
A time management step of synchronizing the time of the network terminal with a predetermined time based on the time synchronization information;
The time synchronization information and the slot table are received from the network management server, according to the time synchronized by the time management unit and the first communication period and the second communication period included in the slot table. A terminal radio control step of communicating between the network management server and the plurality of network terminals by the switched first communication method or the second communication method;
A network management method characterized by comprising: A network management server for managing communication between the plurality of network terminals connected via a network to a plurality of network terminals capable of communicating by a plurality of wireless systems;
A first communication period indicating a period of communication between the network management server and the plurality of network terminals by a first communication method; and a second communication method different from the first communication method, and the network management server and A storage unit for storing a slot table including a second communication period indicating a period of communication in the plurality of network terminals;
A synchronization time management unit for acquiring time synchronization information for synchronizing the time between the plurality of network terminals from the outside;
The time synchronization information and the slot table are transmitted to the plurality of network terminals, the time synchronization information acquired by the synchronization time management unit, and the first communication period and the second communication included in the slot table. A server radio control unit that switches a communication method between the network management server and the plurality of network terminals to either the first communication method or the second communication method based on a period;
A network management server comprising: The slot table further includes a transmission timing of predetermined data transmitted by the first communication method or the second communication method for each of the plurality of network terminals,
The synchronization time management unit determines a transmission timing of the predetermined data based on the slot table;
The network management server according to claim 11. A network terminal capable of communicating by a plurality of wireless systems connected via a network to a network management server that manages communication between a plurality of network terminals,
A time management unit that synchronizes the time of the network terminal with a predetermined time based on time synchronization information for synchronizing the time between the plurality of network terminals;
A first communication period indicating a period of communication between the network management server and the plurality of network terminals by the time synchronization information and the first communication method from the network management server, and a first communication method different from the first communication method. And a slot table including a second communication period indicating a period during which the network management server and the plurality of network terminals communicate with each other according to the communication method, and the time synchronized by the time management unit and the slot table Communication is performed between the network management server and the plurality of network terminals by the switched first communication method or the second communication method according to the included first communication period and the second communication period. A terminal radio control unit;
A network terminal characterized by comprising: The terminal radio control unit transmits the predetermined data to the network management server based on the transmission timing of the slot table received from the network management server;
The network terminal according to claim 12, wherein:

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