JP2010220036A - Gateway device, method of controlling the same, system, program for executing the method, and recording medium with the program recorded therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gateway device executing control to acquire sensing data at data acquisition timing corresponding to a sensing cycle from a sensor node small in the sensing cycle, and executing control to prevent packet collision on a sensor network. <P>SOLUTION: Sensing data acquisition timing is preferentially allocated to sensor nodes small in a sensing cycle in accordance with a sensing cycle of each sensor node (S301-S304). When there is a case, in the sensing data acquisition timing allocated to the respective sensor nodes, where the timing allocated to one of the nodes overlaps the timing allocated to another node, the sensing data acquisition timing allocated to the sensor node large in the sensing cycle is advanced or delayed, thereby the sensing data acquisition timing allocated to one of the nodes is prevented from overlapping the timing allocated to another node (S305, S306). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gateway device for relaying data between networks. More specifically, the present invention relates to a gateway device having a function of transferring data on a sensor network to another network.

  Systems for managing various items and operating devices, both at home and outdoors, have been developed, such as sensor networks and home networks. A sensor network (a device equipped with sensors, microprocessors, wireless chips, power supplies, etc.) dispersed in a wide space automatically observes the surrounding environment and physical conditions, and is based on the observation data. It is a network that performs appropriate operations and enables information sharing by wirelessly communicating observation data between sensor nodes. The type of sensor to be mounted may be any type such as temperature, room temperature, humidity, acceleration, and gas. The sensor network can be used for various purposes, and includes, for example, consumer applications, particularly monitors for industrial instrumentation, living environment, nature protection, health management, traffic conditions, and the like. On the other hand, as shown in, for example, the standardization specifications of an industry group that promotes standardization of home network systems (see Non-Patent Document 1), a system composed of sensor nodes and control devices is isolated and other systems It is rare to operate without cooperation, and most of them operate with some cooperation with an external system. Therefore, a gateway device having a data relay function is installed at a connection point between the system and the external system in order to manage relay of cooperation with the external system. The application node in the external system acquires sensing data (data transmitted by the sensor) from a plurality of sensor nodes constituting the sensor network via the gateway device, and provides the sensing data to the application node. An example of a sensor network system is a sensor network system that includes a gateway device connected to a plurality of sensor nodes via a network, and a server connected to the gateway device via the network. Some special format conversion is applied to the sensing data acquired from the sensor node, which makes it easy to join a new type of sensor node to the existing sensor network system and adopt a new communication standard ( For example, see Patent Document 1).

  On the other hand, for example, Patent Document 2 is a gateway device that performs data transfer between a plurality of networks, and receives a plurality of types of packets (packets having different transmission cycles) received in parallel from a plurality of receiving-side communication paths. There is described a gateway device that changes the transmission order so that a packet with a short transmission cycle is transmitted first to the transmission side communication path instead of transmitting to the transmission side communication path in the order described above. This gateway device has a configuration in which packets are rearranged and the transmission order is changed by controlling a write / read address to / from a memory for temporarily storing packets in accordance with a difference in packet transmission cycle. An object of the present invention is to prevent a packet having a transmission cycle from being unable to be transmitted within a certain transmission cycle due to waiting for transmission of a packet having a long transmission cycle.

JP 2007-243478 A JP 2005-341492 A

ECHONET Part 9 ECHONET Gateway Specification ver3.21 “October 13, 2005” (ECHONET consortium: http://www.echonet.gr.jp/8_kikaku/spec/pdf_v321/SpecVer321_09.pdf)

  Since the characteristics and performance of sensors vary widely, the period at which sensor nodes acquire (sample) sensing data (hereinafter referred to as “sensing period”) also varies. For example, in the case of a system that measures the change in room temperature in a living environment, the sensing period may be long because the change in room temperature is small, but in the case of a monitoring system that uses images, the change in time of the image is large, so sensing It is necessary to shorten the cycle. In a sensor node with a short sensing cycle, if the cycle / timing (hereinafter referred to as “sensing data acquisition timing”) by which the gateway device acquires sensing data from the sensor node varies greatly, the application of the external system connected to the gateway device It can happen that a node cannot get the desired information. Accordingly, a gateway having a configuration capable of acquiring sensing data from a sensor node having a short sensing cycle at a sensing data acquisition timing corresponding to the sensing cycle, that is, a configuration capable of acquiring sensing data at almost the same interval as the sensing cycle. It would be desirable to provide an apparatus.

  On the other hand, in a sensor network system, packet collisions may occur on the sensor network when a plurality of sensor nodes simultaneously transmit sensing data packets to the gateway device. As a countermeasure, when packet loss occurs due to packet collision, a process of resending the packet and recovering data is performed, but the gateway apparatus capable of preventing the packet collision itself on the sensor network It is desirable to provide

  However, Non-Patent Document 1 and Patent Documents 1 and 2 do not describe the above-described configuration. For example, the technique described in Patent Document 2 is received in parallel from a plurality of reception-side communication paths. Since multiple types of packets are temporarily stored in the memory, then the packets are read from the memory, and the packets are multiplexed and transmitted. Therefore, packet collision cannot occur. Therefore, this technique is a technique for preventing packet collision. There is no relevance.

  Therefore, an object of the present invention is to provide a gateway device or the like capable of controlling to acquire sensing data at a sensing data acquisition timing corresponding to the sensing period from a sensor node having a short sensing period. A further object of the present invention is to provide a gateway apparatus and the like capable of controlling packet collision on a sensor network.

  The gateway device of the present invention is a gateway device that can be connected to a plurality of sensor nodes via a network, and stores storage means for storing sensor node information including a sensing cycle corresponding to the sensor node, and sensing read from the storage means In accordance with the period, a determination unit that determines a timing for acquiring sensing data from the sensor node, an allocation unit that allocates the timing determined by the determination unit to each of the sensor nodes, and a timing at which the allocation unit allocates the network. Via the sensor node, the acquisition means for acquiring the sensing data from the sensor node, the determination means compares the sensing periods with each other, determines the timing preferentially for the sensor nodes having a short sensing period, the assignment means, the sensor node The timing decided for each When serving as an, assigned to the sensing period is long sensor node, the timing earlier than the later timing or timing to be identical from the timing when the same.

  The system of the present invention is a system comprising a plurality of sensor nodes, a network connectable to the plurality of sensor nodes, and a gateway device connectable to the plurality of sensor nodes via the network. A storage unit that stores sensor node information including a sensing cycle corresponding to the sensor node, a determination unit that determines timing for obtaining sensing data from the sensor node according to a sensing cycle read from the storage unit, and a determination unit Allocating means for allocating the determined timing to each of the sensor nodes, and acquiring means for acquiring sensing data from the sensor node via the network at the timing allocated by the allocating means. Compare and sense each other The timing is preferentially determined for a sensor node having a short period, and when the timing determined for each sensor node is the same, the timing is later than the same timing for a sensor node having a long sensing cycle. Alternatively, a timing earlier than the same timing is assigned.

  The gateway device control method of the present invention is a gateway device control method connectable to a plurality of sensor nodes via a network, and stores sensor node information including a sensing period corresponding to each of the sensor nodes in a storage means. A storage step, a determination step for determining a timing for acquiring sensing data from the sensor node according to a sensing cycle read from the storage means, an allocation step for assigning the determined timing to each of the sensor nodes, It includes an acquisition step of acquiring sensing data from a plurality of sensor nodes via a network at a timing. In the determination step, the sensing cycles are compared with each other, and the timing is preferentially determined for a sensor node having a short sensing cycle. , Assignment step The flop, if the timing determined for each sensor node is the same, allocated to the sensing period is long sensor node, the timing earlier than the later timing or timing to be identical from the timing when the same.

  According to the present invention, regarding a sensor node having a short sensing cycle, sensing data can be acquired from the sensor node at a data acquisition timing corresponding to the sensing cycle. This is because in the present invention, sensing data acquisition timing is preferentially assigned to a sensor node having a short sensing period according to the sensing period of each sensor node.

  Also, according to the present invention, it is possible to prevent packet collisions on the network because a plurality of sensor nodes are prevented from simultaneously sending sensing data to the network. The reason is that, in the present invention, when there is the same timing among the sensing data acquisition timings assigned to each sensor node, the timing assigned to the sensor node having the longer sensing cycle is advanced or delayed. Because it does.

It is a block diagram which shows an example of the system which has the gateway apparatus which concerns on this Embodiment as a basic element. It is a figure which shows an example of the sensor node information stored in a sensor node information storage part. It is a flowchart which shows the flow of a process by the scheduling part which has a function which allocates the acquisition timing of sensing data to a sensor node. It is a figure which shows an example of the schedule table which a scheduling part produces.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing an example of a system having the gateway device according to the present embodiment as a basic element.

  The system includes a gateway device 101, three application nodes 102 to 104 on an external system, a first network 105 that connects the gateway device 101 and the application nodes 102 to 104, a gateway device 101, and a sensor node 107. To 109 are connected to each other, and a second network (sensor network) 106 and three sensor nodes 107 to 109 are provided. In this example, the number of application nodes and sensor nodes is three, but the number is not limited to these.

The sensor nodes 107 to 109 are small devices having, for example, a sensor function, a wireless communication function, a power supply function, a calculation function (CPU), and the like. Examples of the sensor function include the following functions.
(1) Functions for measuring and observing numerical data of people and things (for example, temperature sensor, humidity sensor, acceleration sensor, infrared sensor, optical sensor, acoustic sensor, magnetic sensor, pressure sensor, water level sensor)
(2) A function for measuring the presence or absence of a person or an object (for example, an infrared sensor or an optical sensor)
(3) Function for reading information stored in advance in the IC chip (for example, RFID tag reader, IC card reader)
(4) Function to shoot images of people and things (for example, network camera)

  In the sensor network, the second network 106 is generally constructed wirelessly so that a large number of sensor nodes can be installed in various places without wiring. However, there may be a case where it is constructed by a wired connection like a home security system.

  The first network 105 is the Internet or the like. The application nodes 102 to 104 transmit sensor node control signals to the gateway apparatus 101 via the first network 105, while receiving sensing data from the gateway apparatus 101.

  When the application nodes 102 to 104 require sensing data, the application nodes 102 to 104 request the sensing data by transmitting a sensor node control signal to the gateway device 101, or the gateway device 101 in advance before the sensing data is required. A sensor node control signal is transmitted. When the application nodes 102 to 104 have transmitted sensor node control signals to the gateway device 101 in advance, the gateway device 101 may be configured to apply the application periodically or when the state of the sensor nodes 107 to 109 changes. Sensing data is transmitted to the nodes 102-104.

  The application nodes 102 to 104 execute predetermined processing (device state monitoring, control, etc.) based on the sensing data received from the gateway device 101.

  The sensor nodes 107 to 109 have a function of transmitting sensing data to each other using a built-in communication function.

  The gateway device 101 is a device that enables communication between the first network 105 and the second network 106 by relaying data. Hereinafter, a configuration example of the gateway device 101 will be described in detail.

  The gateway device 101 includes a sensing data transmission unit 110, a sensor node control signal reception unit 111, a sensing data cache unit 112, a sensing data reception unit 113, a control signal transmission / reception unit 114, a scheduling unit 115, a sensor node And an information storage unit 116.

  The sensor node control signal receiving unit 111 receives the above-described sensor node control signal from the application nodes 102 to 104.

  The control signal transmission / reception unit 114 transmits control signals to the sensor nodes 107 to 109, and receives information about the sensor nodes (hereinafter referred to as “sensor node information”) from the sensor nodes 107 to 109. The sensor node information will be described later.

  The sensor node information storage unit 116 receives the sensor node information from the control signal transmission / reception unit 114 and stores it.

  The sensing data receiving unit 113 receives sensing data packetized from the sensor nodes 107 to 109 via the second network 106.

  The sensing data cache unit 112 temporarily stores the sensing data received by the sensing data receiving unit 113.

  The sensing data transmitting unit 110 receives the sensing data received from the sensing data receiving unit 113 or the sensing data read from the sensing data cache unit 112 as necessary under the control of the sensor node control signal receiving unit 111. And transmitted to the application nodes 102 to 104 via the first network 105.

  FIG. 2 is a diagram illustrating an example of sensor node information stored in the sensor node information storage unit 116.

  In the example illustrated in FIG. 2, the sensor node information includes the sensing cycle of each of the sensor nodes 107 to 109, the application request cycle that is a cycle in which the application nodes 102 to 104 request sensing data to the gateway 101, and The data size of sensing data for one time transmitted from the sensor nodes 107 to 109 to the gateway apparatus 101 is included. Instead of this data size, the number of packets of sensing data for one time transmitted from the sensor nodes 107 to 109 to the gateway device 101 may be used.

  The sensing period is a period at which the sensor nodes 107 to 109 sample sensing data, and this period is determined according to the performance and characteristics of the sensor nodes 107 to 109 or the monitoring target of the sensor nodes 107 to 109. For example, since the state change of the image is fast while the state change of the room temperature is slow, the sensing cycle of the sensor node for image monitoring is set to be relatively short, and the sensing cycle of the sensor node for room temperature observation is set to be relatively long .

In the example shown in FIG. 2, the sensing periods of the sensor nodes 107 to 109 are 10 seconds, 5 seconds, and 6 seconds, respectively. Application request periods are 20 seconds, 5 seconds, and 6 seconds, respectively, and data sizes are 1 Kbyte, 2 Kbyte, and 1 Kbyte, respectively.
Note that the units (seconds, bytes) used here are used for the sake of convenience, and are not limited to these units.

  As described above, the sensor node information is transmitted from the sensor nodes 107 to 109 to the gateway device 101 via the second network 106, and the control signal transmission / reception unit 114 of the gateway device 101 transmits the received sensor node information to the sensor node. The information is stored in the information storage unit 116. However, the configuration is not limited to this configuration, and the sensor node information may be stored in the sensor node information storage unit 116 of the gateway device 101 in accordance with a setting by an administrator who manages the gateway device 101.

  The scheduling unit 115 refers to the sensor node information stored in the sensor node information storage unit 116, obtains the acquisition order when the gateway device 101 acquires sensing data from the plurality of sensor nodes 107 to 109, and Each time a sensing data acquisition timing is assigned.

  FIG. 3 is a flowchart showing a flow of processing by the scheduling unit 115 having a function of assigning sensing data acquisition timing to the sensor nodes 107 to 109.

  In step S301, the scheduling unit 115 compares the sensing periods of a plurality of sensor nodes stored in the sensor node information storage unit 116 with each other, and selects the sensor node with the shortest sensing period. When the sensing cycle as shown in FIG. 2 is stored in the sensor node information storage unit 116, the scheduling unit 115 selects the sensor node 108 because the sensing cycle of the sensor node 108 is the shortest.

  In step S302, the scheduling unit 115 assigns sensing data acquisition timing to the sensor node 108 based on the sensing cycle of the sensor node 108 selected in step S301. That is, the scheduling unit 115 creates a schedule table for the sensor node 108 as shown in FIG.

FIG. 4 is a diagram illustrating an example of a schedule table.
The scheduling unit 115 creates a schedule table in which the sensing data acquisition timing is assigned to the sensor node 108 at intervals of 5 seconds from the reference time, as shown in FIG. The reason for the 5 second interval is that the sensing period of the sensor node 108 is 5 seconds (see FIG. 2).

  In step S303, the scheduling unit 115 selects a sensor node having the shortest sensing cycle among sensor nodes to which sensing data acquisition timing is not yet assigned. In step S302, since the sensing data acquisition timing is assigned to the sensor node 108, the sensor node having the shortest sensing cycle is selected from the sensor nodes 107 and 109, which are sensor nodes other than the sensor node 108. According to FIG. 2, the sensor node 109 having the shortest sensing cycle among the sensor nodes other than the sensor node 108 is the sensor node 109, so the scheduling unit 115 selects the sensor node 109.

  In step S304, the scheduling unit 115 creates a schedule table in which sensing data acquisition timing is assigned to the sensor node 109 at intervals of 6 seconds from the time of (reference time + α), as shown in FIG. 4B. create. The reason why the interval is 6 seconds is that the sensing cycle of the sensor node 109 is 6 seconds (see FIG. 2). Since the sensing data acquisition timing assigned to the sensor node 109 in step S304 may be changed in a later process, the assignment in step S304 is not finalized. Therefore, the assignment in step S304 is referred to as “temporary assignment”.

  In step S305, the scheduling unit 115 checks whether or not the sensing data acquisition timings assigned in step S302 and step S304 may be the same, and if the timings may be the same, the scheduling unit 115 In step S306, the process proceeds to step S306. If the same timing is not reached, the process proceeds to step S307. According to the schedule table shown in FIG. 4B, the sensing data acquisition timing temporarily assigned to the sensor node 109 matches the sensing data acquisition timing assigned to the sensor node 108 at the timing t5. Therefore, the scheduling unit 115 proceeds to the process of step S306.

  In step S306, when there is a timing (in this example, t5) at which the plurality of sensing data acquisition timings are the same as described above, the scheduling unit 115 sets the sensing data acquisition timing for the sensor node having the longer sensing cycle. The sensing data acquisition timings of both are not overlapped by being advanced or delayed.

  According to the schedule table shown in FIG. 4C, the scheduling unit 115 sets the sensing data acquisition timing temporarily assigned to the sensor node 109 at t5 for a predetermined time in order to eliminate the overlapping of the sensing data acquisition timing at t5. Delay. The predetermined time here is, for example, the time required for the sensor node 108 to transmit one sensing data to the gateway device 101. According to FIG. 2, the data size of the sensing data for one time transmitted from the sensor node 108 to the gateway device 101 is 2 KB. Therefore, the scheduling unit 115 delays the sensing data acquisition timing for the sensor node 109 from t5 by the time required for the sensor node 108 to transmit 2 Kbytes of sensing data to the gateway apparatus 101. Here, the time may be obtained using the number of packets of sensing data instead of the data size of the sensing data. On the other hand, the scheduling unit 115 may advance the sensing data acquisition timing temporarily assigned to the sensor node 109 at t5 by a predetermined time. The predetermined time here is, for example, the time required for the sensor node 109 to transmit one sensing data to the gateway device 101. According to FIG. 2, the data size of one sensing data that the sensor node 109 transmits to the gateway device 101 is 1 KB. Therefore, the scheduling unit 115 may advance the sensing data acquisition timing for the sensor node 109 earlier than t5 by the time required for the sensor node 109 to transmit 1 Kbyte of data to the gateway apparatus 101. As described above, the data size (or the number of packets) of one sensing data for the sensor node to transmit to the gateway device 101 is stored in the sensor node information storage unit 116 in advance, and the sensing data acquisition timing is set to the data size. Is delayed or advanced by the transmission time of the sensing data obtained from. Accordingly, it is possible to control a plurality of sensor nodes so as not to simultaneously transmit sensing data packets to the gateway apparatus 101, thereby preventing packet collision on the network.

  In step S307, the scheduling unit 115 determines whether or not the sensing data acquisition timing is assigned to all the sensor nodes 107 to 109, and when there is a sensor node to which the sensing data acquisition timing is not yet assigned. While the process proceeds to step S303, if the sensing data acquisition timing is assigned to all the sensor nodes 107 to 109, the process ends. That is, the scheduling unit 115 repeatedly executes the processes of Steps S103 to S306 until the sensing data acquisition timing is assigned to all the sensor nodes 107 to 109. In the above-described example, the assignment of the sensing data acquisition timing to the sensor node 108 and the sensor node 109 is confirmed, but the sensing data acquisition timing is not yet assigned to the sensor node 107. Therefore, the scheduling unit 115 creates a schedule table in which the sensing data acquisition timing is assigned to the sensor node 107 at intervals of 10 seconds from the time of (reference time + β) as shown in FIG. . The reason why the interval is 10 seconds is that the sensing cycle of the sensor node 107 is 10 seconds (see FIG. 2). As described above, the sensing data acquisition timing assigned to the sensor node 107 at this stage is not fixed, and is shown in step S306 in relation to the sensing data acquisition timing already assigned to another sensor node. There is a possibility that such timing adjustment is performed. Thus, when the assignment of the sensing data acquisition timing to all the sensor nodes 107 to 109 is confirmed, the processing by the scheduling unit 115 ends.

  The schedule table shown in FIG. 4D has been confirmed, and the gateway apparatus 101 refers to this schedule table in the order of sensor nodes 108, 109, 107, 108, 109, 108, 107. To obtain sensing data from each sensor node. As can be seen from this schedule table, since the sensing data acquisition timings do not match, a plurality of sensor nodes do not simultaneously transmit each sensing data packet to the gateway apparatus 101.

  The control signal transmission / reception unit 114 of the gateway device 101 refers to the schedule table created by the scheduling unit 115, transmits a sensing data acquisition request signal as a control signal to the sensor node, and the sensor node that has received the sensing data acquisition request The sensing data is transmitted to the gateway device 101. Thereby, the gateway apparatus 101 can acquire sensing data at an appropriate timing according to the schedule table. As another configuration, the gateway device 101 that is synchronized in advance with the sensor nodes 107 to 109 transmits the schedule table created by the scheduling unit 115 to all the sensor nodes 107 to 109, and each sensor node However, the configuration may be such that the sensing data is autonomously transmitted to the gateway apparatus 101 according to the sensing data acquisition timing assigned to the own node with reference to the schedule table.

  When a new sensor node is added to the second network 106, the scheduling unit 115 of the gateway device 101 performs the process of assigning the sensing data acquisition timing to the sensor node again, and re-reads the sensing data acquisition timing for the sensor node. Assign. Next, the scheduling unit 115 acquires sensing data from the sensor node according to the reassigned sensing data acquisition timing.

  When the sensor node is disconnected from the network, the scheduling unit 115 does not need to redo the process of assigning sensing data acquisition timing. However, like the sensor node 109, when the application request cycle is the same as the sensing cycle and the sensing data acquisition timing is assigned to a timing delayed from t5 due to the relationship with the sensor node 108 as described above, When the sensor node 108 is disconnected, the sensor node 109 is reassigned to t5 which is the original data acquisition timing.

  In this embodiment, a configuration is adopted in which the scheduling unit 115 assigns sensing data acquisition timing to each sensor node in advance before acquiring sensing data. However, in addition to this configuration, the sensing data acquisition timing from the next time onward when sensing data is acquired. May be assigned.

  In the present embodiment, the first network 105 and the second network 106 have been described as different networks. However, the same network may be used, and the gateway device 101 may be operated like a cache server. .

  Further, the present embodiment includes a computer program that executes the series of processes described above and a computer-readable recording medium that records the computer program.

  DESCRIPTION OF SYMBOLS 101 Gateway apparatus, 102-104 Application node, 105 1st network, 106 2nd network, 107-109 Sensor node, 110 Sensing data transmission part, 111 Sensor node control signal receiving part, 112 Sensing data cache part, 113 Sensing data receiving unit, 114 control signal transmitting / receiving unit, 115 scheduling unit, 116 sensor node information storage unit.

Claims (12)

A gateway device connectable to a plurality of sensor nodes via a network,
Storage means for storing sensor node information including a sensing period corresponding to the sensor node;
Determining means for determining the timing for obtaining sensing data from the sensor node according to the sensing period read from the storage means;
Assigning means for assigning the timing determined by the determining means to each of the sensor nodes;
Obtaining means for obtaining the sensing data from the sensor node via the network at a timing assigned by the assigning means;
With
The determining means compares the sensing periods with each other, preferentially determines the timing with respect to a sensor node having a short sensing period,
The assigning means assigns a timing later than the same timing or earlier than the same timing to a sensor node having a long sensing cycle when the timing determined for each sensor node is the same. The gateway apparatus characterized by this. The sensor node information further includes the data size or the number of packets of sensing data corresponding to the sensor node,
The gateway apparatus according to claim 1, wherein the timing is determined based on the data size or the number of packets of sensing data acquired from a sensor node having a short sensing cycle. The sensor node information further includes the data size or the number of packets of sensing data corresponding to each of the sensor nodes,
The gateway device according to claim 1, wherein the timing is determined based on the data size or the number of packets of sensing data acquired from a sensor node having a long sensing cycle. Further connectable to a network connectable to one or more application nodes;
The transmission apparatus according to claim 1, further comprising a transmission unit configured to transmit the sensing data acquired by the acquisition unit to the one or more application nodes via a network connectable to the one or more application nodes. The gateway device according to any one of 1 to 3. A system comprising a plurality of sensor nodes, a network connectable to the plurality of sensor nodes, and a gateway device connectable to the network,
The gateway device is
Storage means for storing sensor node information including a sensing period corresponding to the sensor node;
Determining means for determining the timing for obtaining sensing data from the sensor node according to the sensing period read from the storage means;
Assigning means for assigning the timing determined by the determining means to each of the sensor nodes;
Obtaining means for obtaining the sensing data from the sensor node via the network at a timing assigned by the assigning means;
With
The determining means compares the sensing periods with each other, preferentially determines the timing with respect to a sensor node having a short sensing period,
The assigning means assigns a timing later than the same timing or earlier than the same timing to a sensor node having a long sensing cycle when the timing determined for each sensor node is the same. A system characterized by One or more application nodes and a network connectable to the one or more application nodes;
The gateway device is
The transmission apparatus according to claim 1, further comprising a transmission unit configured to transmit the sensing data acquired by the acquisition unit to the one or more application nodes via a network connectable to the one or more application nodes. 5. The system according to 5. A control method for a gateway device connectable to a plurality of sensor nodes via a network,
A storage step of storing in the storage means sensor node information including a sensing period corresponding to each of the sensor nodes;
A determination step for determining a timing for acquiring sensing data from the sensor node according to the sensing period read from the storage unit;
Assigning the determined timing to each of the sensor nodes;
An acquisition step of acquiring the sensing data from the plurality of sensor nodes via the network at the allocated timing;
Including
In the determining step, the sensing periods are compared with each other, and the timing is preferentially determined for a sensor node having a short sensing period,
In the assigning step, when the timing determined for each sensor node is the same, a timing later than the same timing or earlier than the same timing is assigned to a sensor node having a long sensing cycle. A control method of a gateway device characterized by the above. The sensor node information further includes the data size or the number of packets of sensing data corresponding to each of the sensor nodes,
8. The gateway device control method according to claim 7, wherein the timing is determined based on the data size or the number of packets of sensing data acquired from a sensor node having a short sensing cycle. The sensor node information further includes the data size or the number of packets of sensing data corresponding to each of the sensor nodes,
8. The gateway device control method according to claim 7, wherein the timing is determined based on the data size or the number of packets of sensing data acquired from a sensor node having a long sensing cycle. A control method of a gateway device further connectable to a network connectable to one or a plurality of application nodes,
8. The method according to claim 7, further comprising transmitting the sensing data acquired in the acquiring step to the one or more application nodes via a network connectable to the one or more application nodes. The control method of the gateway apparatus of any one of thru | or 9.   A computer-readable recording medium recording a program for causing a computer to execute the method according to any one of claims 7 to 10.   The program for making a computer perform the method of any one of Claims 7 thru | or 10.

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