JP5187281B2 - Gateway device - Google Patents

Description

  The present invention relates to a gateway device that relays packets between communication networks.

  2. Description of the Related Art In recent years, network systems for managing various things and operating devices, both home and outdoors, called so-called sensor networks and home networks have been developed. For example, a standardized specification of an industry group for building a home network such as Non-Patent Document 1 has been formulated.

  In general, a sensor network system operates in cooperation with other systems. For example, a data processing node belonging to the other system (a node having an application for processing data; hereinafter referred to as an application node) represents sensor data representing, for example, temperature and rainfall from the sensor node belonging to the sensor network system. To obtain data and process the data. Gateway devices are installed to relay data between the sensor network system and other systems, and these systems can transmit and receive data to and from each other via the gateway device.

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

  By the way, when a plurality of sensor nodes transmit packets to the gateway device with the application node as a destination, so-called packet collision occurs and packet loss occurs. The lost packet is retransmitted by the source node of the packet. In this case, the retransmission time is between the desired data acquisition time preset in the data processing node and the actual data acquisition time. There was a difference of only minutes. Therefore, there is a problem that data cannot be acquired or accurate data processing cannot be performed even if it can be acquired.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a gateway device that allows an application node to acquire data at a desired timing.

  A gateway apparatus according to the present invention is a gateway apparatus that relays a packet between at least two communication networks, and includes a data request including a specified node and a specified period from at least one data request node belonging to one of the communication networks. A receiving unit that receives a signal, a storage unit that stores at least the number of hops for each node belonging to the other of the communication network, and the designated node based at least on the number of hops corresponding to each of the designated nodes and the designated period A packet transmission timing setting unit that sets a packet transmission timing for each packet; and a transmission unit that transmits a packet transmission request signal for requesting packet transmission at the packet transmission timing to each of the designated nodes. .

  According to the gateway device of the present invention, the application node can acquire data at a desired timing.

It is a block diagram showing a gateway apparatus with a sensor node etc. FIG. It is a block diagram showing a gateway apparatus. It is a figure showing a network configuration table. It is a figure showing an application request table. It is a flowchart showing a packet transmission timing setting processing routine. It is a schematic diagram showing packet transmission timing. It is a schematic diagram showing another packet transmission timing.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing the gateway device 1 according to the present embodiment together with the sensor node 4-1-1. The gateway device 1 is a packet relay device that relays packets between a communication network 2-1 such as the Internet and a communication network 2-2 such as a sensor network. The application node 3-1 is a node that includes an application for processing data included in a packet received via the gateway device 1. For example, temperature or rainfall obtained by a sensor included in the sensor node 4-1-1. This is a data processing node that performs analysis processing of data representing the quantity and the like. Each of the application nodes 3-2 to 3-n (n is a positive integer) has the same configuration as that of the application node 3-1.

  The sensor node 4-1-1 includes, for example, a sensor for detecting temperature and rainfall, generates data representing the temperature and rainfall obtained by the sensor, and includes a packet transmission request including a packet transmission timing from the gateway device 1. It is a node that transmits the data to a destination application node (any one of 3-1 to 3-n) according to a signal. Each of the sensor nodes 4-1-2 to 4-4-2 has the same configuration as that of the sensor node 4-1-1, and each of them communicates with each other, for example, tree routing according to the specifications of ZigBee (registered trademark) Holds the path information obtained by. The gateway device 1 can also acquire, hold, and use this path information. A so-called tree-type communication network constituted by the sensor nodes 4-1-1-4-4-2 is a communication network 2-2. The communication network 2-2 may further include a plurality of other sensor nodes, or the communication network 2-2 may be configured with a smaller number of sensor nodes than those shown in FIG. .

  FIG. 2 is a block diagram showing the gateway device 1. The gateway device 1 includes a packet reception unit 10, an AP data conversion unit 11, a signal transmission unit 12, a signal reception unit 13, a sensor data conversion unit 14, a packet transmission unit 15, a network information management unit 16, A network information storage unit 17, a sensor data request information storage unit 18, and a packet transmission timing setting unit 19 are included.

  The packet receiving unit 10 receives packets from the application nodes 3-1 to 3-n that have arrived via the communication network 2-1. The AP data conversion unit 11 converts the format of the packet received by the packet receiving unit 10 into a format suitable for transmission to the communication network 2-2. The signal transmission unit 12 transmits the packet signal obtained by the format conversion by the AP data conversion unit 11 to the communication network 2-2. Hereinafter, the packet reception unit 10, the AP data conversion unit 11, and the signal transmission unit 12 are collectively referred to as a packet relay unit 20. That is, the packet relay unit 20 relays the packet from the transmission source node that has arrived via the communication network 2-1 to the transmission destination node via the communication network 2-2. In addition to such relaying, the signal transmission unit 12 has a function of transmitting a packet including a packet transmission request signal generated by a packet transmission timing setting unit 19 described later via the communication network 2-1.

  The signal receiver 13 receives packet signals from the sensor nodes 4-1-1 to 4-4-2 that have arrived via the communication network 2-2. The sensor data converter 14 converts the format of the packet signal received by the signal receiver 13 into a format suitable for transmission to the communication network 2-1. The packet transmission unit 15 transmits the packet obtained by the format conversion by the sensor data conversion unit 14 to the communication network 2-1. Hereinafter, the signal reception unit 13, the sensor data conversion unit 14, and the packet transmission unit 15 are collectively referred to as a signal relay unit 21. That is, the signal relay unit 21 relays the packet signal from the transmission source node that has arrived via the communication network 2-2 to the transmission destination node via the communication network 2-1.

  The network information management unit 16 manages information about the network topology configured by the sensor nodes 4-1-1 to 4-4-2 belonging to the communication network 2-2. The information is, for example, the number of hops or the number of child nodes for each sensor node. When the network topology of the communication network 2-2 is a cluster tree type topology configured in accordance with, for example, the ZigBee specification, the network information management unit 16 transmits packets from the sensor nodes 4-1-1 to 4-4-2. From the 2-byte short address included in the address field, for example, the configuration of the network topology such as the number of hops and the number of child nodes for each sensor node is analyzed. As a ZigBee network address, a 16-bit short address defined in IEEE 802.15.4 is used.

  The network information storage unit 17 is information about the network topology configured by the sensor nodes 4-1-1 to 4-4-2 belonging to the communication network 2-2, such as the number of hops and the number of child nodes for each sensor node. For example, a storage medium such as a hard disk or a RAM. The information may be acquired by the network information management unit 16 or may be input in advance by a network administrator or the like. Specifically, the network information storage unit 17 stores these pieces of information as a network configuration table.

  FIG. 3 is a diagram illustrating a network configuration table. The “node identifier” is an identifier representing each of the sensor nodes 4-1-1 to 4-4-2. The “hop count” is the number of times that a packet is transmitted by the sensor node before reaching the gateway device 1. For example, when the sensor node 4-1-1 transmits a packet, it is once, and when the sensor node 4-4-1 transmits a packet, the sensor nodes 4-4-1, 4-3-1. Since it is transmitted by 4-2-1 and 4-1-1, it is four times. “Number of child nodes” is the number of nodes (child nodes) that belong to a certain node in the tree structure. In other words, the number of child nodes is the number of nodes that cannot transmit a packet to the gateway device 1 unless the packet is relayed by that node. For example, there is no child node for the sensor node 4-4-1 and the number of child nodes is zero. The child nodes for the sensor node 4-3-1 are sensor nodes 4-4-1 and 4-4-2, and the number of child nodes is two. The network configuration table stores these pieces of information for each of the sensor nodes 4-1-1 to 4-4-2 belonging to the communication network 2-2.

  The sensor data request information storage unit 18 includes a packet (hereinafter referred to as a data request signal) that is received by the packet receiving unit 10 and includes a data transmission request to the sensor node (4-1-1 to 4-4-2). Also, a storage medium such as a hard disk or a RAM for storing data such as a specified node and a specified period included in the data. Specifically, the sensor data request information storage unit 18 stores these pieces of information as an application request table.

  FIG. 4 is a diagram illustrating an application request table. The “application node identifier” is an identifier such as an IP address that is unique to the application node (any one of 3-1 to 3-n) that has issued the data transmission request. The transmission source address indicated in the header of the packet including the data transmission request received by the packet receiving unit 10 is stored as the “application node identifier”. Here, for the sake of convenience, it is represented as 3-1. The “sensor node identifier” is an identifier unique to each node such as an IP address indicating any one of the sensor nodes 4-1-1 to 4-2-2 included in the data transmission request. The identifier is the sensor node (4-1-1 to 4-4-2) that the application node (3-1 to 3-n) that issued the data transmission request should acquire the sensor data. Is used to specify Hereinafter, a node designated by the identifier is also referred to as a designated node. Here, for convenience, it is expressed as 4-4-1.

  For example, when the “application node identifier” is 3-1 and the “sensor node identifier” is 4-4-1, the application node 3-1 acquires the sensor data held by the sensor node 4-4-1. Therefore, the sensor node 4-4-1 is designated as the designated node. The “designated period” is a period in which the application node (any one of 3-1 to 3-n) that has issued the data transmission request designates a period for acquiring sensor data. For example, if the “application node identifier” is 3-1 and the “designated period” is 10, it indicates that the application node 3-1 wants to acquire sensor data at intervals of 10 seconds. Each time the packet reception unit 10 receives a packet including a data transmission request, the sensor data request information storage unit 18 sequentially stores these pieces of information in the application request table.

  The packet transmission timing setting unit 19 is configured for each designated node based on the information in the network configuration table stored in the network information storage unit 17 and the information in the application request table stored in the sensor data request information storage unit 18. Set the packet transmission timing. Here, the packet transmission timing is a timing at which the designated node should transmit a packet to the application node, and includes an initial transmission time and a transmission cycle.

  The packet transmission timing setting unit 19 determines a sensor node to preferentially set the packet transmission timing based on the number of hops and the number of child nodes included in the network configuration table, and based on the specified period included in the application request table. The packet transmission timing for the sensor node is set. The packet transmission timing setting unit 19 performs such setting for each designated node, and generates a packet transmission request signal (packet signal) including the packet transmission timing. The packet transmission request signal is transmitted to the designated node (any one of the sensor nodes 4-1-1 to 4-4-2) via the communication network 2-1 by the signal transmission unit 12.

  The function of each block such as the packet transmission timing setting unit 19 described above can be realized as hardware by a microprocessor having an arithmetic processing function such as a CPU, and software can be executed by executing a computer program that realizes these functions. Can also be realized.

  FIG. 5 is a flowchart showing a packet transmission timing setting processing routine. Hereinafter, the packet transmission timing setting process by the packet transmission timing setting unit 19 will be described with reference to FIG. The packet transmission timing setting unit 19 executes the routine each time a packet including a data transmission request is received by the packet receiving unit 10.

  First, the packet transmission timing setting unit 19 responds to a data transmission request with sensor node identifiers (designated nodes) 4-4-1, 4-2-1 and 4-4-1 stored in the application request table (FIG. 4). The one having the largest number of hops out of 2-3 is selected with reference to the network configuration table (FIG. 3) (step S101). Specifically, the sensor node identifier 4-4-1 in the network configuration table has 4 hops, 4-2-1 has 2 hops, and 4-2-3 has 2 hops. The packet transmission timing setting unit 19 selects the sensor node identifier 4-4-1 having the largest number of hops.

  Next, the packet transmission timing setting unit 19 determines that, among the sensor node identifiers stored in the application request table, the sensor node identifier having a hop count of 4 is only 4-4-1 (step S102). Step S103 is not executed, and the routine goes to Step S104.

  Subsequently, the packet transmission timing setting unit 19 sets the packet transmission timing for the sensor node 4-4-1 (step S104). The packet transmission timing includes an initial transmission time and a transmission cycle of sensor data by the sensor node 4-4-1. The packet transmission timing setting unit 19 sets, for example, a time after a predetermined time has elapsed as the initial transmission time T0 from the reception time of the packet including the data transmission request by the packet reception unit 10. Here, the predetermined time is, for example, sufficient time for a packet from the gateway device 1 to reach the sensor node 4-4-1 via the communication network 2-1.

  Further, the packet transmission timing setting unit 19 sets a designated cycle for the sensor node 4-4-1 stored in the application request table as a transmission cycle. In this case, the designated period is, for example, 10 seconds. The packet transmission timing set in this way is as shown in FIG. 6A. The sensor node 4-4-1 transmits the first packet A0 at the initial transmission time T0, and then the initial transmission time T0. Represents that the second packet A1 should be transmitted at time T3 after the lapse of 10 seconds from the specified period, and then packets A2,.

  The packet transmission timing setting unit 19 generates a packet transmission request signal for requesting packet transmission at this packet transmission timing, and causes the signal transmission unit 12 to transmit the signal to the sensor node 4-4-1 (step S105).

  The packet transmission timing setting unit 19 determines that the packet transmission timing setting for the sensor node identifiers 4-2-1 and 4-2-3 has not been completed (step S106), and also for these node identifiers, step S101. Execute sequentially from the process.

  The packet transmission timing setting unit 19 has one sensor with the largest number of hops because the sensor node identifier 4-2-1 in the network configuration table has two hops and 4-2-3 has two hops. It is determined that the node identifier cannot be selected (steps S101 and S102), and the process proceeds to step S103.

  In this case, the packet transmission timing setting unit 19 selects the sensor node identifier 4-2-1 and 4-2-3 having the largest number of child nodes with reference to the network configuration table (step S103). . Specifically, since the number of child nodes of the sensor node identifier 4-2-1 in the network configuration table is 4 and the number of child nodes of 4-2-3 is 0, the packet transmission timing setting unit 19 The sensor node identifier 4-2-1 having the largest number is selected.

  Subsequently, the packet transmission timing setting unit 19 sets the packet transmission timing for the sensor node 4-2-1 (step S104). The packet transmission timing includes an initial transmission time and a transmission cycle of sensor data by the sensor node 4-2-1. The packet transmission timing setting unit 19 sets, for example, a time after a predetermined time has elapsed from the initial transmission time T0 for the previously set sensor node 4-4-1 as the initial transmission time T1. Here, the fixed time is, for example, the transmission cycle of 10 seconds for the previously set sensor node 4-4-1 is the number of sensor node identifiers stored in the application request table (3 in the case of FIG. 3). The time obtained by the division is about 3.3 seconds. In this case, the time after about 3.3 seconds from the initial transmission time T0 for the sensor node 4-4-1 is set as the initial transmission time T1 for the sensor node 4-2-1.

  Further, the packet transmission timing setting unit 19 sets the designated cycle for the sensor node 4-2-1 stored in the application request table as the transmission cycle. In this case, the designated period is, for example, 10 seconds. As shown in FIG. 6B, the packet transmission timing set in this way is the first packet transmitted by the sensor node 4-2-1 at the initial transmission time T1 after about 3.3 seconds from the time T0. B0 is transmitted, and then the second packet B1 is transmitted at time T4 after 10 seconds from the initial transmission time T1, and subsequently, packets B2,. Indicates that it should be sent.

  The packet transmission timing setting unit 19 generates a packet transmission request signal for requesting packet transmission at this packet transmission timing, and causes the signal transmission unit 12 to transmit the signal to the sensor node 4-2-1 (step S105).

  The packet transmission timing setting unit 19 determines that the packet transmission timing setting for the sensor node identifier 4-2-3 has not been completed (step S106), and the node identifier 4-2-3 is also processed from the process of step S101. Run sequentially. The packet transmission timing setting unit 19 sets the packet transmission timing for the sensor node identifier 4-2-3 by the same process as described above (step S104). As shown in FIG. 6C, the set packet transmission timing is such that the sensor node 4-2-3 transmits the first packet C0 at the initial transmission time T2 after about 3.3 seconds from the time T1. Then, the second packet C1 should be transmitted at the time T5 after 10 seconds from the initial transmission time T2, and then the packets C2,. Represents the effect.

  The packet transmission timing setting unit 19 generates a packet transmission request signal for requesting packet transmission at this packet transmission timing, and causes the signal transmission unit 12 to transmit it to the sensor node 4-2-3 (step S105). The packet transmission timing setting unit 19 determines that the setting of packet transmission timing for all sensor nodes has been completed (step S106), and ends the packet transmission timing setting processing routine.

  The above example is an example in which the initial transmission time for each sensor node is set as an interval of about 3.3 seconds, but the setting of the initial transmission time is not limited to this, and the initial transmission time for each sensor node is All you have to do is set them so that they do not overlap.

  Further, a larger number of packet transmissions may be assigned to the sensor node that is determined to have a higher priority by the processes in steps S101 to S103 as compared to other sensor nodes. For example, each sensor node within a period of 30 seconds, which is the sum of the designated periods for each of the sensor node identifiers 4-4-1, 4-2-1 and 4-2-3 in the network configuration table (FIG. 3). Make a difference in the number of packet transmissions. FIG. 7 is a schematic diagram showing packet transmission timing when there is a difference in the number of packet transmissions by each sensor node within a predetermined period of 30 seconds.

  First, the packet transmission timing setting unit 19 adds, for example, the sum (30 seconds each) of the designated cycle (each 10 seconds) for each of the sensor node identifiers 4-4-1, 4-2-1 and 4-2-3 in the application request table. Seconds). Next, the packet transmission timing setting unit 19 calculates the packet transmission interval as about 3.3 seconds as in the above example. When the packet transmission interval is about 3.3 seconds, nine packets can be transmitted within a predetermined period of 30 seconds. Therefore, the packet transmission timing setting unit 19 allocates these nine packets to the above-described three sensor nodes in a priority order of, for example, a ratio of 3: 2: 1. In this case, for example, 5 times for the sensor node 4-4-1, 3 times for the sensor node 4-2-1, and 1 time for the sensor node 4-2-3 in the 30 seconds. Each packet transmission count is assigned. If it is not divisible by the ratio calculation, the number of packet transmissions is calculated by rounding off or rounding off the decimal point as appropriate.

  When the number of packet transmissions is set as described above, the packet transmission timing for each sensor node is set as shown in FIG. 7, for example. Specifically, the sensor node 4-4-1 is set to transmit packets five times at intervals of about 3.3 seconds between times T0 and T4, and the sensor node 4-2-1 Between T5 and T7, settings were made to transmit packets three times at intervals of about 3.3 seconds, and sensor node 4-2-3 was set to transmit packets once at time T8. It will be.

  For example, when each of the packets A0 to A4 is the same data, even if the application node 3-1 cannot receive the packet A0 due to a packet collision, it is only necessary to receive any of the packets A1 to A4. Is substantially expanded, and the application node 3-1 can easily acquire data at a desired timing.

  The packet transmission timing setting unit 19 generates a packet transmission request signal including these packet transmission timings for each sensor node, and causes the signal transmission unit 12 to correspond to each corresponding sensor node (4-4-1, 4-2). 1 and 4-2-3). In this way, the number of packet transmissions can be set for each sensor node in accordance with the priority obtained based on the number of hops and the number of child nodes.

  As described above, the gateway device according to this embodiment sets the packet transmission timing in descending order of the number of hops and the number of child nodes for each sensor node. In general, as the number of hops and child nodes increases, packet collision is more likely to occur. Therefore, the gateway device according to the present embodiment sets the packet transmission timing in preference to a node having a larger number of hops and child nodes. It becomes difficult to occur. As a result, since there is no need for packet retransmission, the difference between the desired packet acquisition time and the actual packet acquisition time at the application node is reduced. Therefore, the application node can acquire data at a desired timing.

  Further, the gateway device according to the present embodiment allocates more packet transmission times in order from the sensor node having the largest number of hops and child nodes (packet collision is likely to occur) when setting the packet transmission timing for each sensor node. Can do. By continuously transmitting packets by sensor nodes that are likely to encounter packet collisions, a substantial margin is provided in the packet acquisition period in the application node, making it easier for the application node to acquire data at a desired timing. There is an effect.

  In addition, although a present Example is an example in case the node which comprises the communication network 2-2 is a sensor node, and the communication network 2-2 is a sensor network, the communication network 2-2 is various in home, for example It may be another network such as a home network composed of nodes that control devices.

DESCRIPTION OF SYMBOLS 1 Gateway apparatus 2-1 and 2-2 Communication network 3-1 to 3-n Application node (data request node)
4-1-1 to 4-4-2 Sensor node (node, designated node)
10 Packet receiver (receiver)
11 AP data converter 12 Signal transmitter (transmitter)
13 Signal receiver 14 Sensor data converter 15 Packet transmitter 16 Network information manager 17 Network information storage (storage)
18 Sensor data request information storage unit 19 Packet transmission timing setting unit 20 Packet relay unit 21 Signal relay unit

Claims (7)

A gateway device that relays packets between at least two communication networks,
A receiving unit for receiving a data request signal including a designated node and a designated period from at least one data requesting node belonging to one of the communication networks;
A storage unit for storing at least the number of hops for each node belonging to the other of the communication network;
A packet transmission timing setting unit that sets a packet transmission timing for each designated node based at least on the number of hops corresponding to each of the designated nodes and the designated period;
And a transmission unit that transmits a packet transmission request signal for requesting packet transmission at the packet transmission timing to each of the designated nodes.   The gateway apparatus according to claim 1, wherein the packet transmission timing setting unit sets the packet transmission timing in an order in which priority is given to a designated node having a large number of hops among the designated nodes. The storage unit further stores the number of child nodes for each node belonging to the other of the communication network,
The gateway apparatus according to claim 1, wherein the packet transmission timing setting unit sets the packet transmission timing based on the designated period, the hop count, and the child node count.   When the packet transmission timing setting unit determines that there are two or more designated nodes having the same number of hops, the packet transmission timing setting unit prioritizes a designated node having a larger number of child nodes among the designated nodes. The gateway device according to claim 3, wherein the gateway device is set. The packet transmission timing includes an initial transmission time,
5. The gateway apparatus according to claim 1, wherein the packet transmission timing setting unit sets the initial transmission times of the designated nodes so as not to overlap each other. 6.   The gateway apparatus according to claim 5, wherein the packet transmission timing setting unit sets the designated cycle as a packet transmission cycle and includes the packet transmission timing in the packet transmission timing.   The packet transmission timing setting unit is configured such that the number of packet transmissions within a predetermined period of a designated node having a relatively large number of hops is greater than the number of packet transmissions in the predetermined period of a designated node having a relatively small number of hops. The gateway apparatus according to claim 5, wherein the packet transmission timing for each designated node is set.

Images