JP5406130B2 - Communications system - Google Patents

Description

  The present invention relates to a communication system including a mesh network having a plurality of communication nodes.

  Conventionally, in communication between devices, data is transmitted and received by directly connecting a terminal (communication node) as a transmission source and a communication node as a reception destination. In this case, there is an advantage that it is easy to understand because it is possible to secure a route for performing the desired communication by directly connecting the communication node and the communication node.

  However, when the number of communication partners increases, the number of connections required for communication between communication nodes becomes necessary. Therefore, for example, when it is necessary to communicate with all the communication nodes, there is a problem that the connection becomes complicated.

  As one method of solving such a problem, for example, as a wireless LAN access point, any one communication node is set as a base point (base point node), and the communication node relays each communication. There is a method for enabling communication nodes to communicate with each other.

  In the case of the method using the base point node, since the base point node relays communication of all the communication nodes, the communication is concentrated, so that the load on the base point node becomes very large. Therefore, a mesh network has been devised in which any one communication node does not undertake communication relay, but all communication nodes can serve as relay stations (see, for example, Patent Document 1).

  FIG. 26 shows an example of a mesh network. The mesh network 100 shown in FIG. 26 includes nodes (communication nodes) A to E. Node A is connected to node B so that they can communicate with each other. Node B is connected to nodes A, C, and D so that they can communicate with each other. Node C is connected to nodes B and E so that they can communicate with each other. Node D is connected to nodes B and E so that they can communicate with each other. Node E is connected to nodes C and D so that they can communicate with each other.

  In a mesh network, when data is transmitted to a target communication node in communication, data is transmitted to a neighboring communication node even if it cannot be directly transmitted. Then, the communication node to which the data has been transmitted further transmits the data to neighboring communication nodes. By repeating this, data can be transmitted to the target communication node. For example, in the mesh network 100 shown in FIG. 26, when data is transmitted from the node A to the node E, the data of the node B is transmitted from the node A, and then the data is transmitted from the node B to the node C. Data is transmitted from node C to node E. Alternatively, data may be transmitted from the node B to the node E through the node D. Since data is transmitted in this way, the load of data relay is not concentrated on one communication node, and communication can be efficiently performed as a whole.

  In such a mesh network, in order to deliver data to a target communication node, each communication node selects a route so that the number of relays is reduced as much as possible. Therefore, it is possible to reduce unnecessary relays and efficiently use the network as the entire communication network.

  In a conventional mesh network, for example, as in Patent Document 2, it is common to configure each communication node to select a route with as few relay points as possible.

Japanese Patent Laid-Open No. 4-368034 JP 2006-20302 A

  However, in a mesh network, since the number of relays differs depending on each communication node, data generated later than data generated earlier in time may reach the receiving communication node earlier. For example, in the case of FIG. 26, when data (referred to as data D) occurs at node D after data (referred to as data A) generated at node A, data A and data D are generated in the order in which the data occurred. However, the data D may reach the node E first.

  In this case, since the order of arrival data is changed, when processing must be performed in the order of data generation, for example, the node E (or the entire network) needs to manage the order of data generation. For example, FIG. 26 is a network relating to vehicle window control, in which node A is a window open / close lock button, node D is a window open / close button, and node E is a device that operates a window. If the window opening / closing is operated after the window opening / closing lock button is operated and locked, the window is not opened / closed correctly. However, as described above, the data D, that is, the window opening / closing button If the data indicating the above operation reaches the node E first, it leads to a malfunction in which the window operates despite being locked when viewed as the entire vehicle window.

  As described above, when the mesh network is applied to a control system application, the influence of the data arrival order problem due to the difference in the number of relays is increased.

  Therefore, an object of the present invention is to provide a communication system in which the arrival order of data to communication nodes can be the order of occurrence of data in a mesh network.

  In order to solve the above-mentioned problem, the invention according to claim 1 comprises a mesh network having a plurality of communication nodes each including a receiving means for receiving data and a transmitting means for transmitting data. In the communication system, the data includes a destination and a communication time that has elapsed until reception by the receiving unit, and the maximum communication time in the mesh network and all of the data connected to the mesh network from itself Communication condition storage means in which the communication time to the communication node is stored in advance, and destination determination means for determining whether the data is addressed to itself or another communication node based on the destination of the data received by the receiving means When the destination determination unit determines that the data received by the reception unit is addressed to another communication node, the communication condition storage unit An addition value obtained by adding the communication time to the destination stored in the communication condition storage means to the communication time elapsed until the reception means receives the data received by the reception means and the maximum communication time stored in the communication means When the added value is the same value as the maximum communication time, the transmission means transmits the data to the destination or relay destination communication node, and the added value is greater than the maximum communication time. If it is smaller, communication control means for controlling the transmission means to transmit to the communication node of the destination or relay destination after waiting the data for the time obtained by subtracting the added value from the maximum communication time, A communication system comprising the communication node.

  According to a second aspect of the present invention, in the first aspect of the present invention, the data includes the number of relays relayed until reception by the reception unit, and the communication condition storage unit includes the mesh. The maximum number of relays in the network and the number of relays from itself to all the communication nodes connected to the mesh network are stored in advance, and the communication control means includes the maximum number of relays stored in the communication condition storage means Compared with the addition value obtained by adding the number of relays to the destination stored in the communication condition storage unit to the number of relays relayed until the reception unit receives the data received by the reception unit, and the addition value Is the same value as the maximum number of relays, the transmission means transmits the data to the destination or relay destination communication node, and the added value is greater than the maximum number of relays. If it is smaller, the data is controlled to wait for the number of relays obtained by subtracting the added value from the maximum number of relays, and then transmitted to the destination or relay destination communication node. Is.

  According to a third aspect of the present invention, in the second aspect of the present invention, the communication control means relays the relay until it is received by the receiving means when the added value is smaller than the maximum number of relays. The number is incremented and the data is transmitted from its own transmission means to its reception means.

  According to a fourth aspect of the present invention, in the invention according to the second or third aspect, when the communication control unit receives the reception value by the reception unit when the addition value is the same as the maximum number of relays. The number of relayed relays is incremented, and the data is transmitted from the transmission means to the destination or relay destination.

  According to a fifth aspect of the present invention, in the first aspect of the present invention, the data includes a transmission time consumed in a communication path until the data is received by the receiving unit. The maximum transmission time in the mesh network and the transmission time from itself to all the communication nodes connected to the mesh network are stored in advance, and the communication control means stores the maximum transmission time stored in the communication condition storage means. A transmission time and an addition value obtained by adding the transmission time to the destination stored in the communication condition storage means to the transmission time consumed in the communication path until the reception means receives the data received by the reception means. In comparison, if the added value is the same value as the maximum transmission time, the transmitting means transmits the data to the destination or relay destination communication node, When the added value is smaller than the maximum transmission time, the transmission means waits for the transmission time obtained by subtracting the added value from the maximum transmission time and then transmits the data to the destination or relay destination communication node. It is characterized by controlling to make it happen.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, when the communication control unit consumes the communication channel before receiving by the receiving unit when the added value is smaller than the maximum transmission time. A predetermined reference transmission time is added to the transmitted time, and the data is transmitted from the transmission means to the reception means.

  According to a seventh aspect of the present invention, in the invention according to the fifth or sixth aspect, when the communication control unit receives the addition value when the addition value is the same value as the maximum transmission time, The transmission time to the destination is added to the transmission time consumed in the communication path, and the data is transmitted from the transmission means to the destination or relay destination.

  The invention according to an eighth aspect is the invention according to any one of the first to seventh aspects, wherein when the destination determination means determines that the data received by the reception means is addressed to itself, the reception is performed. The communication node includes reception data confirmation means for judging whether the data is normal based on the communication time elapsed until reception by the means and the maximum communication time stored in the communication condition storage means. It is characterized by that.

  As described above, according to the first aspect of the present invention, the communication control means has the maximum communication time in the mesh network stored in the communication condition storage means and all communication nodes connected to the mesh network from itself. Based on the communication time to the destination, the destination included in the data, and the communication time that has elapsed until reception by the receiving means, an addition value that is obtained by adding the communication time to the destination to the maximum communication time and the communication time that has elapsed before reception is If they are not the same, they are sent to the adjacent communication node after waiting for the difference time. That is, since the communication time between the communication nodes is matched with the maximum communication time of the mesh network, the data arrival order does not differ from the data generation order even if the number of relays is different. In addition, it is not necessary to manage the order of data in an application such as a system, apparatus, or software that processes arrived data, and can be configured simply.

  According to the second aspect of the present invention, the data includes the number of relays relayed until reception by the reception unit, and the communication condition storage unit stores the maximum number of relays in the mesh network and the number of relays from itself to the mesh network. The number of relays to all connected communication nodes is stored in advance, and the communication control means relays until the maximum number of relays stored in the communication condition storage means and the data received by the receiving means are received by the receiving means. The added value obtained by adding the number of relays to the destination stored in the communication condition storage means to the number of relays that have been added is the same as the maximum number of relays. If it is sent to the communication node and the added value is smaller than the maximum number of relays, the transmission means waits for the number of relays obtained by subtracting the added value from the maximum number of relays, and then the destination means or relay destination communication Since the number of relays is used as the communication time and the number of relays from the transmission source to the destination is matched with the maximum number of relays in the mesh network, data is transmitted even if the number of relays is different. The arrival order of the data is no longer different from the data generation order.

  According to the third aspect of the invention, when the added value is smaller than the maximum number of relays, the communication control unit increments the number of relayed relays until reception by the receiving unit, and transmits itself from its own transmitting unit. Since the data is transmitted to the receiving means, the number of relays can be adjusted by the number of virtual transmission / reception inside, and the communication time can be waited with a simple configuration.

  According to the fourth aspect of the present invention, when the addition value is the same value as the maximum number of relays, the communication control unit increments the number of relays relayed until reception by the receiving unit and sends from the transmission unit to the destination. Alternatively, since the data is transmitted to the relay destination, the number of relays relayed until reception by the receiving means is updated, and the normality of communication at the destination and the relay destination is confirmed with the updated number of relays. And the number of relays can be adjusted.

  According to the fifth aspect of the present invention, the data includes the transmission time consumed in the communication path until it is received by the receiving means, and the communication condition storage means includes the maximum transmission time in the mesh network and the transmission time. The transmission time to all communication nodes connected to the mesh network is stored in advance, and the communication control means receives the maximum transmission time stored in the communication condition storage means and the data receiving means received by the receiving means. The transmission time consumed in the communication path is compared with an addition value obtained by adding the transmission time to the destination stored in the communication condition storage means, and if the addition value is the same value as the maximum transmission time, data is sent to the transmission means. Is sent to the destination or adjacent communication node, and if the addition value is smaller than the maximum transmission time, the transmission time obtained by subtracting the addition value from the maximum transmission time is made to wait. From the transmission source to the destination using the transmission time consumed on the communication path calculated from the transmission speed between the communication nodes as the communication time. Therefore, even if the transmission time is different, the data arrival order is not different from the data generation order. Further, even in a mesh network in which transmission times between communication nodes are different, data can be made to reach a target communication node in the order of generation.

  According to the sixth aspect of the present invention, when the communication control means has the added value smaller than the maximum transmission time, the reference transmission time set in advance to the transmission time consumed in the communication path until reception by the receiving means. Since the data is transmitted from its own transmission means to its own reception means, the transmission time can be adjusted by the number of additions of the reference transmission time by virtual transmission / reception inside.

  According to the seventh aspect of the present invention, when the communication control means has the same value as the maximum transmission time, the reference determined in advance for the transmission time consumed in the communication path until reception by the reception means. Since the transmission time is added and data is transmitted from the transmission means to the destination or relay destination, the transmission time consumed in the communication path until the reception means receives it is updated, and the updated transmission time is used. It is possible to check the normality of communication at the destination and relay destination and adjust the transmission time.

  According to the eighth aspect of the present invention, when the destination determination unit determines that the data received by the reception unit is addressed to itself, the destination is stored in the communication time and communication condition storage unit that has elapsed until reception by the reception unit. Since the communication node has a reception data confirmation means for judging whether or not the data is normal based on the maximum communication time, the communication time (number of relays or transmission time) elapsed until reception by the reception means is calculated. By confirming, it is possible to confirm whether the data has been correctly transmitted.

1 is a configuration diagram of a communication system according to a first embodiment of the present invention. It is explanatory drawing which shows the structural example of the communication frame as data transmitted within the communication system shown by FIG. It is a block diagram which shows the structure of the communication node shown by FIG. It is a flowchart which shows operation | movement of the communication node shown by FIG. 3 is a table showing a communication path table of a node A shown in FIG. 2 is a table showing a communication path table of a Node B shown in FIG. 3 is a table showing a communication path table of a node C shown in FIG. It is a table | surface which shows the communication route table of the node D shown by FIG. It is a table | surface which shows the communication route table of the node E shown by FIG. It is explanatory drawing which shows transmission of the communication frame in the communication system shown by FIG. It is a block diagram of the communication system concerning the 2nd Embodiment of this invention. It is explanatory drawing which shows the structural example of the communication frame as data transmitted within the communication system shown by FIG. It is a block diagram which shows the structure of the communication node shown by FIG. 14 is a flowchart illustrating an operation of the communication node illustrated in FIG. 13. 12 is a table showing a communication path table of the node A shown in FIG. 12 is a table showing a communication path table of the node B shown in FIG. 12 is a table showing a communication path table of a node C shown in FIG. 12 is a table showing a communication path table of a node D shown in FIG. 12 is a table showing a communication path table of the node E shown in FIG. 12 is a table showing adjacent node base transmission time of node A shown in FIG. 11. 12 is a table showing adjacent node base transmission time of Node B shown in FIG. 11. 12 is a table showing adjacent node base transmission time of node C shown in FIG. 11. 12 is a table showing adjacent node base transmission times of the node D shown in FIG. 11. 12 is a table showing adjacent node base transmission time of the node E shown in FIG. 11. It is explanatory drawing which shows transmission of the communication frame in the communication system shown by FIG. It is a block diagram of the communication system using the conventional mesh network.

(First embodiment)
Next, a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the communication system 1 according to the first embodiment of the present invention includes a plurality of communication nodes 20 (node A, node B, node C, node D, and node E). These nodes A to E constitute a mesh network.

  In the communication system 1 shown in FIG. 1, the node A is connected to the node B so as to communicate with each other. Node B is connected to nodes A, C, and D so that they can communicate with each other. Node C is connected to nodes B and E so that they can communicate with each other. Node D is connected to nodes B and E so that they can communicate with each other. Node E is connected to nodes C and D so that they can communicate with each other. In the present embodiment, it is assumed that the communication speed between the communication nodes 20 is the same.

  FIG. 2 shows a configuration example of a communication frame 50 as data transmitted in the communication system 1. The communication frame 50 includes communication source information 51, destination information 52, a hop number 53, and communication data 54. The frame length of the communication frame 50 is fixed.

  The communication source information 51 stores information (for example, node A) indicating the communication node 20 of the communication source that generated the communication frame 50, and the destination information 52 is information (for example, information indicating the communication node 20 of the communication frame 50). Node E).

  The number of hops 53 stores the number of hops (the number of relays) relayed until reception by the data receiving unit 3, which is the communication time elapsed until reception by the receiving unit, and the communication data 54 is stored in the destination communication node 20. Stores data used in.

  FIG. 3 shows a block diagram of the communication node 20. The communication node 20 includes a communication unit 2, a data reception unit 3 as a reception unit, a destination determination unit 4 as a destination determination unit, an application notification unit 5 as a reception data confirmation unit, and a data relay as a communication control unit A selection unit 6, a communication path table 7 as a communication condition storage unit, a maximum hop number storage unit 8 as a communication condition storage unit, a hop number predictor 9 as a communication control unit, and a data transmission unit as a transmission unit 10 and a virtual communication path 11.

  The communication unit 2 is a block for inputting / outputting a communication frame 50 to / from the outside. The communication frame 50 input from the outside is output to the data receiving unit 3, and the communication frame 50 input from the data transmitting unit 10 is external Is output.

  The data receiving unit 3 receives a communication frame 50 input from the communication unit 2 or a virtual communication path 11 described later, and outputs the communication frame 50 to the destination determination unit 4.

  The destination determination unit 4 analyzes the destination information 52 in the communication frame 50 and outputs the communication frame 50 to the application notification unit 5 when it is the communication frame 50 addressed to itself, and is addressed to another communication node 20. In this case, the communication frame 50 is output to the data relay selection unit 6.

  When the application notification unit 5 receives the communication frame 50 addressed to itself, the application notification unit 5 notifies the application executed in its own communication node 20, extracts the communication data 54 in the communication frame 50, and delivers it to the application. Further, it is determined whether or not the received communication frame 50 is normal from the hop number 53 of the received communication frame 50 and the maximum hop number stored in the maximum hop number storage unit 8 described later. Further, when data to other communication nodes 20 is generated by the application, the data is received from the application, a communication frame 50 is generated and output to the destination determination unit 4. The application refers to a unit (for example, window lock) that executes a function assigned to the communication node 20 among devices and systems (for example, vehicle window control) realized in the entire communication system 1. Although not shown in the figure, it is configured by hardware or software.

  The data relay selection unit 6 selects a relay station necessary for transmitting the received communication frame 50 to the destination communication node 20 with reference to the communication path table 7 described later. The data relay selection unit 6 causes the received communication frame 50 and a communication path table 7 described later to predict the total number of hops to the destination of the communication frame 50 using a hop number predictor 9 described later, and a hop number predictor. If the total number of hops predicted in step 9 is compared with the maximum number of hops stored in the maximum number of hops storage unit 8 to be described later, The number of hops 53 in the frame 50 is incremented (+1) and the communication frame 50 is output to the data transmission unit 10. If the predicted total number of hops is smaller than the maximum number of hops, the number of hops 53 in the communication frame 50 is set. Increment and output the communication frame 50 to the virtual communication path 11.

  The communication path table 7 indicates the number of hops to the communication nodes 20 other than itself constituting the communication system 1, that is, the communication time (number of relays) from all of the communication nodes 20 connected to the mesh network, If there is a relay station and if there is a relay station, the relay station name (information that can indicate the relay station such as an address) is stored in advance in a table for each communication node 20.

  The maximum hop count storage unit 8 stores in advance the maximum hop count (maximum number of relays) as the maximum communication time in the communication system 1. In this embodiment, the communication path table 7 and the maximum hop count storage unit 8 are configured separately, but may be configured such that each area is provided in one memory or the like.

  The hop number predictor 9 receives the communication frame 50 and the total number of hops from the communication path table 7 to the destination of the communication frame 50, that is, the hops to the destination stored in the communication path table 7 in the hop number 53 of the communication frame 50. Predict the sum of numbers.

  The data transmission unit 10 outputs the communication frame 50 input from the data relay selection unit 6 to the communication unit 2.

  The virtual communication path 11 transmits the communication frame 50 from the data relay selection unit 6 to the data reception unit 3 in order to virtually transmit the communication frame 50 within the communication node 20.

  Next, the operation of the communication node 20 configured as described above will be described with reference to the flowchart of FIG.

  First, in step S101, it is determined whether or not data has occurred within itself. If it has occurred (in the case of Y), the process proceeds to step S102, and if it has not occurred (in the case of N), the process proceeds to step S110. In this step, for example, it is determined whether or not the application notification unit 5 has received data to be transmitted from the application to another communication node 20.

  Next, in step S102, the communication frame 50 is generated and the process proceeds to step S103. In this step, since data to be transmitted to another communication node 20 is generated by the application, a communication frame 50 is generated from the data received by the application notification unit 5 and output to the destination determination unit 4.

  Next, in step S103, the communication path table 7 is referred to and the process proceeds to step S104. In this step, the data relay selection unit 6 refers to information on a relay station (destination if it can be directly transmitted to the destination) necessary for transmitting the communication frame 50 generated by the application notification unit 5 to the destination communication node 20. ing.

  Next, in step S104, the total number of hops is predicted and the process proceeds to step S105. In this step, the data relay selection unit 6 makes the hop number predictor 9 predict the total number of hops to the destination of the communication frame 50.

  Next, in step S105, it is determined whether or not the total number of hops predicted in step S104 is the same as the maximum number of hops. If the number is the same (in the case of Y), the process proceeds to step S106. ) Proceeds to step S108.

  Next, in step S106, the hop number 53 in the communication frame 50 is added (incremented), and the process proceeds to step S107. In this step, since the predicted total number of hops is the same as the maximum number of hops, the data relay selection unit 6 increments the number of hops 53 in the communication frame 50 and outputs the communication frame 50 to the data transmission unit 10. Yes.

  Next, in step S107, communication is performed to the next communication node 20. In this step, the communication frame 50 is transmitted from the data transmission unit 10 to the destination or relay destination communication node 20 via the communication unit 2.

  In step S108, the hop number 53 in the communication frame 50 is added (incremented), and the process proceeds to step S109. In this step, since the predicted total number of hops is not the same as the maximum number of hops, the data relay selection unit 6 increments the number of hops 53 in the communication frame 50 before performing internal communication addressed to the own node.

  Next, in step S109, internal communication addressed to its own node is performed, and the process returns to step S101. In this step, the communication frame 50 is transmitted from the data relay selection unit 6 to the data reception unit 3 via the virtual communication path 11. Therefore, when performing internal communication addressed to the own node, the data relay selection unit 6 also serves as a transmission means.

  On the other hand, in step S110, it is determined whether or not data has been received from the adjacent communication node 20. If it is data reception (in the case of Y), the process proceeds to step S111, and if it is not data reception (in the case of N). Return to step S101.

  Next, in step S111, the destination is confirmed and the process proceeds to step S112. In this step, the destination determination device 4 analyzes the destination information 52 in the communication frame 50 to determine whether it is addressed to itself or to another communication node 20.

  Next, in step S112, it is determined whether or not it is addressed to its own node as a result of step S111. If it is addressed to its own node, the process proceeds to step S113. If it is not addressed to its own node, the process proceeds to step S103.

  Next, in step S113, the number of hops is confirmed, and the process proceeds to step S114. In this step, the application notification unit 5 extracts and confirms the hop number 53 in the communication frame 50 addressed to the own node.

  Next, in step S114, it is determined whether or not the number of hops 53 confirmed in step S113 is the same as the maximum number of hops stored in the maximum hop count storage unit 8. The process proceeds to S115, and if not the same (N), the process proceeds to step S116. In this step, the application notification unit 5 makes a determination by comparing the hop count 53 with the maximum hop count.

  Next, in step S115, since the hop number 53 is the same as the maximum hop number, the application notification unit 5 notifies the application of the arrival of the communication data 54 as a normal communication frame.

  In step S116, since the hop number 53 is not the same as the maximum hop number, the communication frame 50 is discarded as an abnormal communication frame.

  Next, an operation example of the communication system 1 (mesh network) having a plurality of communication nodes 20 having the above-described configuration will be described. 5 to 9 show the contents of the communication path table 7 to the nodes A to E. In addition, the maximum number of hops of the mesh network constituting the communication system 1 is “3”, and this value is stored in the maximum hop number storage unit 8 of each communication node 20 in advance.

  First, as Example 1, a case where communication is performed from node A to node E will be described. In node A, when communication data 54 is generated, the information of the own node is set as the communication source information 51, the node E is set as the destination information 52, and the hop number 53 is generated in the own node and relayed from other nodes and received. Since it is not the communication frame 50, the communication frame 50 set to “0” is generated. Then, referring to the communication path table 7 (FIG. 5) of the node A, it can be seen that the destination node E has a relay station and the relay station is the node B. Since the current hop count 53 is 0 hops and the hop count to the node E is 3 hops from the communication path table 7, the total hop count required for communication to the node E is predicted to be 0 + 3 = 3 hops. The On the other hand, the maximum number of hops in the mesh network is 3 hops, and since the predicted total number of hops is the same as the maximum number of hops, the hop number 53 of the communication frame 50 is incremented and set to “1” and relayed immediately. The communication frame 50 is transmitted to the node B which is a station.

  In the node B, the destination information 52 of the communication frame 50 received from the node A is confirmed. Since the destination information 52 is not addressed to itself, referring to the communication path table 7 (FIG. 6) of the node B, the destination node E has a relay station. It can be seen that the relay station is node C. Further, since the current hop count 53 is 1 hop and the hop count to the node E is 2 hops from the communication path table 7, the total hop count required for communication to the node E is predicted to be 1 + 2 = 3 hops. The On the other hand, the maximum number of hops in the mesh network is 3 hops, and since the predicted total number of hops is the same as the maximum number of hops, the hop number 53 of the communication frame 50 is incremented and set to “2” and relayed immediately. The communication frame 50 is transmitted to the node C which is a station.

  In the node C, the destination information 52 of the communication frame 50 received from the node B is confirmed. Since the destination information 52 is not addressed to itself, when referring to the communication path table 7 (FIG. 7) of the node C, the destination node E has no relay station. I understand that there is. Further, since the current hop count 53 is 2 hops and the hop count to the node E is 1 hop from the communication route table 7, the total hop count required for communication to the node E is predicted to be 2 + 1 = 3 hops. The On the other hand, the maximum number of hops in the mesh network is 3 hops, and since the predicted total hop count is the same as the maximum hop count, the hop count 53 of the communication frame 50 is incremented and set to “3”, and the destination immediately The communication frame 50 is transmitted to the node E.

  In the node E, the destination information 52 of the communication frame 50 received from the node C is confirmed, and it can be seen that it is addressed to itself. Further, since the hop number 53 is 3 hops and is the same as the maximum hop number, it is understood that the communication frame is normally communicated, so that the arrival of data is notified to the application and the communication data 54 is delivered.

  In this example 1, operations such as comparing the predicted total hop count with the maximum hop count and incrementing the hop count 53 are performed, but the transmission itself of the communication frame 50 is the same as before. Next, a case where communication is performed from the node D to the node E will be described as Example 2.

  In node D, when communication data 54 is generated, the local node information is set as communication source information 51, node E is set as destination information 52, and the hop number 53 is generated in the local node and is not relayed from other nodes. A communication frame 50 set to “0” is generated. Then, referring to the communication path table 7 (FIG. 8) of the node D, it can be seen that the destination node E has no relay station. Since the current hop count 53 is 0 hop and the hop count to the node E is 1 hop from the communication route table 7, the total hop count required for communication to the node E is predicted to be 0 + 1 = 1 hop. The On the other hand, the maximum number of hops in the mesh network is 3 hops, and since the predicted total number of hops is smaller than the maximum number of hops, the hop number 53 of the communication frame 50 is incremented and set to “1”. The communication frame 50 is transmitted to the data receiving unit 3 via That is, the communication frame 50 is transmitted within itself (self node), and the number of hops is adjusted by one time.

  The node D confirms the destination information 52 of the communication frame 50 received via the virtual communication path 11 at the next timing, and since it is not addressed to itself, referring to the communication path table 7 (FIG. 8) of the node D, the node D It can be seen that a certain node E has no relay station. Since the current hop count 53 is 1 hop and the hop count to the node E is 1 hop from the communication path table 7, the total hop count required for communication to the node E is predicted to be 1 + 1 = 2 hops. The On the other hand, the maximum number of hops in the mesh network is 3 hops, and since the predicted total number of hops is smaller than the maximum number of hops, the hop number 53 of the communication frame 50 is incremented and set to “2”. The communication frame 50 is transmitted to the data receiving unit 3 via

  The node D confirms the destination information 52 of the communication frame 50 received via the virtual communication path 11 at the next timing, and since it is not addressed to itself, the node D refers to the communication path table 7 (FIG. 8) of the node D. It can be seen that node E is without a relay station. Further, since the current hop count 53 is 2 hops and the hop count to the node E is 1 hop from the communication route table 7, the total hop count required for communication to the node E is predicted to be 2 + 1 = 3 hops. The On the other hand, the maximum number of hops in the mesh network is 3 hops, and since the predicted total hop count is the same as the maximum hop count, the hop count 53 of the communication frame 50 is incremented and set to “3”, and the destination immediately The communication frame 50 is transmitted to the node E.

  In the node E, the destination information 52 of the communication frame 50 received from the node D is confirmed, and it can be seen that it is addressed to itself. Further, since the hop number 53 is 3 hops and is the same as the maximum hop number, it is understood that the communication frame is normally communicated, so that the arrival of data is notified to the application and the communication data 54 is delivered.

  In this example 2, since the communication node 20 is close and the number of hops is smaller than the maximum number of hops, node D performs a virtual transmission process for two hops and the number of hops becomes the same as the maximum number of hops. It is adjusted so that. That is, the communication frames 50 are kept waiting for the number of hops obtained by subtracting the total number of hops from the maximum number of hops.

  Here, in the communication system 1 that performs the above-described operation, a case where the communication data 54 is first generated at the node A, and then the communication data 54 is generated at the node D and is transmitted to the node E with reference to FIG. explain.

  As shown in FIG. 10, the communication data 54 generated at the node A is relayed to the nodes B and C as a communication frame 50 and transmitted to the node E. This transmission takes 3 hops. The communication data 54 generated at the node D is transmitted as a communication frame 50 to the node E after being adjusted by two hops inside the node D. This transmission also takes 3 hops. Therefore, since both communications require 3 hops, the communication data 54 of the node A generated earlier reaches the node E earlier than the communication data 54 of the node D generated later.

  According to the present embodiment, the data relay selection unit 6 receives the number of hops to the destination communication node 20 stored in the communication path table 7 and the maximum number of hops stored in the maximum hop number storage unit 8. If the total hop count obtained by adding the hop count to the destination communication node 20 to the maximum hop count and the hop count 53 based on the hop count 53 included in the communication frame 50 is not the same, the hop count 53 is incremented and itself Since the communication frame 50 is transmitted to the data receiving unit 3 via the virtual communication path 11 in the network, the number of hops of communication performed in the network can be matched with the maximum number of hops, Even if the number of communication nodes 20 is different, the arrival order of communication data does not differ from the generation order of communication data. In addition, the number of relays can be adjusted by the number of virtual transmissions / receptions within the communication node 20, and the communication time can be waited with a simple configuration. Furthermore, since it is not necessary to manage the order of data in the application, the application can be configured simply.

  If the total hop count obtained by adding the hop count to the destination communication node 20 to the maximum hop count and the hop count 53 is the same, the hop count 53 is incremented and the destination or relay destination communication is performed. Since the communication frame 50 is transmitted to the node 20, the number of hops 53 can be updated, and the normality of communication can be confirmed and the number of relays can be adjusted at the destination and the relay destination with the updated number of relays.

  When the application notification unit 5 determines that the communication frame 50 received by the destination determination unit 4 at the data reception unit 3 is addressed to itself, the communication frame is normal based on the hop number 53 and the maximum hop number. Therefore, by confirming the number of hops, it is possible to confirm whether the data has been correctly transmitted.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. Note that the same parts as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

  FIG. 11 shows a configuration diagram of the communication system 1 of the embodiment. The communication system 1 shown in FIG. 11 has the same mesh network configuration as that of the first embodiment. In the first embodiment, the communication speed between the communication nodes 20 is assumed to be the same. However, in the present embodiment, the communication speed is different as shown in FIG.

  FIG. 12 shows a configuration example of the communication frame 50 as data transmitted in the present embodiment. The communication frame 50 differs from the communication frame 50 of the first embodiment in that the hop number 53 is replaced with a count value 55.

  The count value 55 is a transmission time consumed in the communication path until reception by the data receiving unit 3, which is a communication time that has elapsed until reception by the reception unit, with a predetermined reference transmission time as one count, that is, a transmission source Stored is a value representing the transmission time consumed by the route from the node to the node as a count value. This count value is set based on the transmission speed on the communication path. For example, when the transmission rate is 2 Mbps, 11 counts are set, and when the transmission rate is 11 Mbps, 2 counts are set so that the count value increases as the transmission rate decreases. In this example, 1 count = 22 Mbps. In other words, the time (seconds) required to transfer 22 Mbit data is the count value.

  FIG. 13 shows a block diagram of the communication node 20 of the present embodiment. In the present embodiment, a maximum transmission time storage unit 14 is provided instead of the maximum hop number storage unit 8, a transmission time predictor 12 is provided instead of the hop number predictor 9, and the adjacent node base transmission time is used as a communication condition storage unit. A storage unit 13 is additionally provided. Further, in response to the change and addition of these blocks, the data relay selection unit 6 is changed to the data relay selection unit 6 ′, and the communication path table 7 is changed to the communication path table 7 ′.

  The maximum transmission time storage unit 14 is stored in advance by converting the maximum transmission time in the communication system 1 into the count value described above.

  The communication path table 7 ′ is converted into the count value described above instead of the number of hops to the communication nodes 20 other than itself constituting the communication system 1 instead of the number of hops to the communication nodes 20 constituting the communication system 1. Has been stored.

  The transmission time predictor 12 predicts the count value from the received communication frame 50 and the communication path table 7 ′ to the destination of the communication frame 50.

  The adjacent node base transmission time storage unit 13 stores a base transmission time between itself and the adjacent communication node 20 (transmission time consumed on the communication path to the adjacent node) as a count value. The maximum transmission time storage unit 14 and the adjacent node base transmission time storage unit 13 may be configured such that each area is provided in one memory or the like together with the communication path table 7 as in the first embodiment. Good.

  The data relay selection unit 6 ′ selects a relay station necessary for transmitting the communication frame 50 received with reference to the communication path table 7 ′ to the destination communication node 20. Further, the data relay selection unit 6 causes the transmission time predictor 12 to predict the total transmission time (count value) from the received communication frame 50 and the communication path table 7 ′ to the destination of the communication frame 50, and also predicts the transmission time. The total transmission time predicted by the device 12 and the count value indicating the maximum transmission time stored in the maximum transmission time storage unit 14 are compared, and the predicted count value and the count value indicating the maximum transmission time are the same. Is incremented by the count value 55 in the communication frame 50 (adding one count as the reference transmission time) and outputs the communication frame 50 to the data transmission unit 10, and the predicted count value indicates the maximum transmission time. When the count value is smaller than the indicated count value, the count value 55 in the communication frame 50 is incremented and the communication frame 50 is output to the virtual communication path 11. That.

  Next, the operation of the communication node 20 configured as described above will be described with reference to the flowchart of FIG.

  First, in step S201, it is determined whether or not data has been generated within itself (if Y), the process proceeds to step S202. If not (N), the process proceeds to step S210. In this step, for example, it is determined whether or not the application notification unit 5 has received data to be transmitted from the application to another communication node 20.

  Next, in step S202, the communication frame 50 is generated and the process proceeds to step S203. In this step, since data to be transmitted to another communication node 20 is generated by the application, a communication frame 50 is generated from the data received by the application notification unit 5 and output to the destination determination unit 4.

  Next, in step S203, the process proceeds to step S204 with reference to the communication path table 7 ′. In this step, the data relay selection unit 6 ′ refers to information on a relay station (destination if it can be directly transmitted to the destination) necessary for transmitting the communication frame 50 generated by the application notification unit 5 to the destination communication node 20. doing.

  Next, in step S204, the transmission time is calculated (predicted), and the process proceeds to step S205. In this step, the data relay selection unit 6 ′ causes the transmission time predictor 12 to predict the total transmission time (count value) to the destination of the communication frame 50.

  Next, in step S205, it is determined whether or not the count value predicted in step S204 is the same as the count value indicating the maximum transmission time. If the count value is the same (in the case of Y), the process proceeds to step S206. In the case of N), the process proceeds to step S208.

  Next, in step S206, the count value up to the relay destination communication node 20 is read from the adjacent node base communication time storage unit 13 and added to the count value 55 in the communication frame 50, and the process proceeds to step S207. In this step, since the predicted count value is the same as the count value indicating the maximum transmission time, the data relay selection unit 6 'sets the transmission time to the relay destination communication node 20 to the count value 55 in the communication frame 50. The corresponding count value is added and the communication frame 50 is output to the data transmission unit 10.

  Next, in step S207, communication is performed to the next communication node 20. In this step, the communication frame 50 is transmitted from the data transmission unit 10 to the adjacent communication node 20 via the communication unit 2.

  In step S208, the count value 55 in the communication frame 50 is added (incremented), and the process proceeds to step S209. In this step, since the predicted count value is not the same as the count value indicating the maximum transmission time, the data relay selection unit 6 ′ transmits the reference transmission to the count value 55 in the communication frame 50 before performing internal communication addressed to the own node. One count which is time is added.

  Next, in step S209, internal communication addressed to its own node is performed, and the process returns to step S201. In this step, the communication frame 50 is transmitted from the data relay selection unit 6 ′ to the data reception unit 3 via the virtual communication path 11.

  On the other hand, in step S210, it is determined whether or not data has been received from the adjacent communication node 20. If the data has been received (in the case of Y), the process proceeds to step S211. If not, the data has not been received (in the case of N). The process returns to step S201.

  Next, in step S211, the destination is confirmed, and the process proceeds to step S212. In this step, the destination determination device 4 analyzes the destination information 52 in the communication frame 50 to determine whether it is addressed to itself or to another communication node 20.

  Next, in step S212, it is determined whether or not it is addressed to the own node as a result of step S211. If it is addressed to the own node, the process proceeds to step S213, and if not addressed to the own node, the process proceeds to step S203.

  Next, in step S213, the communication time is confirmed, and the process proceeds to step S214. In this step, the application notification unit 5 extracts and checks the count value 55 in the communication frame 50 addressed to the own node.

  Next, in step S214, it is determined whether or not the count value 55 confirmed in step S213 is the same as the count value indicating the maximum transmission time stored in the maximum communication transmission storage unit 11. If YES), the process proceeds to step S215. If not (NO), the process proceeds to step S216. In this step, the application notification unit 5 makes a determination by comparing the count value 55 with the count value indicating the maximum transmission time.

  Next, in step S215, since the count value 55 is the same as the count value indicating the maximum transmission time, the application notification unit 5 notifies the application of the arrival of the communication data 54 as a normal communication frame.

  In step S216, since the count value 55 is not the same as the count value indicating the maximum transmission time, the communication frame 50 is discarded as an abnormal communication frame.

  Next, an operation example of the communication system 1 (mesh network) having a plurality of communication nodes 20 having the above-described configuration will be described. 15 to 19 show the contents of the communication path table 7 to the nodes A to E. The count value indicating the maximum transmission time of the mesh network constituting the communication system 1 is “17”, and this value is stored in the maximum transmission time storage unit 14 of each communication node 20 in advance.

  In this embodiment, the adjacent node base transmission time is stored in the adjacent node base transmission time storage unit 13, and the base transmission time between itself and the adjacent communication node 20 is counted as shown in FIGS. Stored as a value.

  First, as Example 1, a case where communication is performed from node A to node E will be described. In node A, when communication data 54 is generated, the local node information, the communication source information 51, and node E are set as destination information 52, and the count value 55 is generated in the local node and is not transmitted from another node. A communication frame 50 set to “0” is generated. Then, referring to the communication path table 7 of the node A (FIG. 15), it can be seen that the destination node E has a relay station and the relay station is the node B. Since the current count value 55 is “0” and the count value up to the node E is “17” from the communication path table 7, the total count value required for communication up to the node E is predicted to be 0 + 17 = 17. Is done. On the other hand, the count value indicating the maximum transmission time of the mesh network is “17”, and the count value indicating the maximum transmission time is the same as the predicted count value. With reference to the time storage unit 13 (FIG. 20), the count value “11” up to the relay station Node B is added and set to “11”, and the communication frame 50 is immediately transmitted to the Node B.

  In the node B, the destination information 52 of the communication frame 50 received from the node A is confirmed. Since the destination information 52 is not addressed to itself, referring to the communication path table 7 (FIG. 16) of the node B, the destination node E has a relay station. It can be seen that the relay station is node D. Since the current count value 55 is “11” and the count value up to the node E is “6” from the communication path table 7, the total count value required for communication up to the node E is predicted to be 11 + 6 = 17. Is done. On the other hand, the count value indicating the maximum transmission time of the mesh network is “17”, and the count value indicating the maximum transmission time is the same as the predicted count value. With reference to the time storage unit 13 (FIG. 21), the count value “4” up to the node D which is the relay station is added and set to “15”, and the communication frame 50 is immediately transmitted to the node D.

  In the node D, the destination information 52 of the communication frame 50 received from the node B is confirmed. Since the destination information 52 is not addressed to itself, referring to the communication path table 7 (FIG. 18) of the node D, I understand that there is. Since the current count value 55 is “15” and the count value up to the node E is “2” from the communication path table 7, the total number of hops required for communication up to the node E is predicted to be 15 + 2 = 17. Is done. On the other hand, the count value indicating the maximum transmission time of the mesh network is “17”, and the count value indicating the maximum transmission time is the same as the predicted count value. With reference to the time storage unit 13 (FIG. 23), the count value “2” up to the destination node E is added and set to “17”, and the communication frame 50 is immediately transmitted to the node E.

  In the node E, the destination information 52 of the communication frame 50 received from the node D is confirmed, and it can be seen that it is addressed to itself. Further, since the count value 55 is “17”, which is the same as the count value indicating the maximum transmission time, it can be seen that the communication frame is normally communicated. Hand over.

  In this example 1, operations such as comparing the predicted count value with the count value indicating the maximum transmission time and adding the count value 55 are performed, but the transmission of the communication frame 50 is the same as the conventional one. Next, a case where communication is performed from the node D to the node E will be described as Example 2.

  In node D, when communication data 54 is generated, the local node information, communication source information 51, and node E are set as destination information 52, and the count value 55 is data generation in the local node and is not relayed from other nodes. A communication frame 50 set to “0” is generated. Then, referring to the communication path table 7 (FIG. 18) of the node D, it can be seen that the destination node E has no relay station. Since the current count value 55 is “0” and the count value up to the node E is “2” from the communication path table 7, the total count value required for communication up to the node E is predicted to be 0 + 2 = 2. Is done. On the other hand, the count value indicating the maximum transmission time of the mesh network is “17”, and since the predicted count value is smaller than the count value indicating the maximum transmission time, 1 count is added to the count value 55 of the communication frame 50. It is set to “1”, and the communication frame 50 is transmitted to the data receiving unit 3 through the virtual communication path 11. That is, the communication frame 50 is transmitted within itself, and the count value is adjusted by one count.

  The node D confirms the destination information 52 of the communication frame 50 received via the virtual communication path 11, and since it is not addressed to itself, referring to the communication path table 7 (FIG. 18) of the node D, the destination node E relays You can see that there is no station. Since the current count value 55 is “1” and the count value up to the node E is “2” from the communication path table 7, the total count value required for communication up to the node E is predicted to be 1 + 2 = 3. Is done. On the other hand, the count value indicating the maximum transmission time of the mesh network is “17”, and since the predicted count value is smaller than the count value indicating the maximum transmission time, 1 count is added to the count value 55 of the communication frame 50. “2” is set, and the communication frame 50 is transmitted to the data receiving unit 3 through the virtual communication path 11. This is repeated until the count value 55 reaches “15” (that is, the number of differences between the count value indicating the maximum transmission time and the count value up to the node E). A count value “2” up to the destination node E is added to the count value 55 with reference to the adjacent node base transmission time storage unit 13 (FIG. 23), and set to “17”. Frame 50 is transmitted.

  In the node E, the destination information 52 of the communication frame 50 received from the node D is confirmed, and it can be seen that it is addressed to itself. Further, since the count value 55 is “17”, which is the same as the count value indicating the maximum transmission time, it can be seen that the communication frame is normally communicated. Hand over.

  In this example 2, since the communication node 20 is close and the count value is smaller than the count value indicating the maximum transmission time, the node D performs a virtual transmission process for 15 counts and performs the count value which is the communication time. Is adjusted. That is, the communication frame 50 is made to wait for a count value obtained by subtracting a value obtained by adding the count value up to the node E to the count value 55 from the count value indicating the maximum transmission time.

  Here, in the communication system 1 that performs the above-described operation, communication data 54 is first generated at node A, communication data 54 is then generated at node D, and both are transmitted to node E with reference to FIG. explain.

  As shown in FIG. 25, the communication data 54 generated at the node A is relayed to the nodes B and D as a communication frame 50 and transmitted to the node E. This transmission takes 17 counts. The communication data 54 generated at the node D is transmitted as a communication frame 50 to the node E after being adjusted by 15 counts inside the node D. This transmission also takes 17 counts. Therefore, since both communications require 17 counts, the communication data 54 of the node A generated first arrives at the node E first, and the communication data 54 of the node D generated later reaches the node E later.

  According to the present embodiment, the data relay selection unit 6 ′ calculates the count value to the destination communication node 20 stored in the communication path table 7 ′ and the maximum transmission time stored in the maximum transmission time storage unit 14. When the count value indicating the maximum transmission time and the added value obtained by adding the count value to the destination communication node 20 to the count value 55 are not the same based on the count value indicated and the count value 55 included in the received communication frame 50 Since 1 count is added to the count value 55 and the communication frame 50 is transmitted to its own data receiving unit 3 via its own virtual communication path 11, the transmission time of the communication frame 50 performed in the network is reduced. It can be adapted to the maximum transmission time, and the arrival order of communication data may differ from the order of occurrence of communication data even if the number of communication nodes 20 passing through is different. Disappear. Further, even in a mesh network in which the transmission times between the communication nodes 20 are different, the communication data 54 can reach the target communication node 20 in the order of generation.

  Note that the virtual communication path 11 does not necessarily need to be a physical communication path (wiring, cable, etc.). For example, a software loop or timer can be used as long as it can take a communication time of one hop or one count. You may carry out by processing etc.

  The communication path between the communication nodes 20 in the communication system 1 described above may be wired or wireless. Of course, both may be mixed.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

1 Communication System 3 Data Receiving Unit (Receiving means)
4 Destination determiner (destination determination means)
5 Application notification part (reception data confirmation means)
6, 6 'data relay selection unit (communication control means, transmission means)
7, 7 'communication path table (communication condition storage means)
8 Maximum number of hops storage (communication condition storage means)
9 Hop number predictor (communication control means)
10 Data transmission unit (transmission means)
12 Transmission time predictor (communication control means)
13 Adjacent node base transmission time storage (communication condition storage means)
14 Maximum transmission time storage (communication condition storage means)
20 Communication node 50 Communication frame (data)
52 Destination information 53 Number of hops (communication time elapsed until reception by receiving means, number of relays relayed until receiving by receiving means)
55 count value (communication time elapsed until reception by reception means, transmission time consumed by communication path until reception by reception means)

Claims (8)

In a communication system comprising a mesh network having a plurality of communication nodes comprising a receiving means for receiving data and a transmitting means for transmitting data,
The data includes a destination and a communication time that has elapsed until reception by the receiving means,
Communication condition storage means in which the maximum communication time in the mesh network and the communication time from itself to all the communication nodes connected to the mesh network are stored in advance,
Destination determination means for determining whether the data is addressed to itself or another communication node based on the destination of the data received by the reception means;
When the destination determination means determines that the data received by the reception means is addressed to another communication node, the maximum communication time stored in the communication condition storage means and the reception means of the data received by the reception means Compared with an addition value obtained by adding the communication time to the destination stored in the communication condition storage means to the communication time elapsed until reception, and if the addition value is the same value as the maximum communication time When the transmission means transmits the data to the destination or relay destination communication node, and the addition value is smaller than the maximum communication time, the data is waited for a time obtained by subtracting the addition value from the maximum communication time. Communication control means for controlling the transmission means to transmit to the destination or relay destination communication node, and
The communication node is provided with a communication system. The data includes the number of relays relayed until reception by the receiving means,
The communication condition storage means stores in advance the maximum number of relays in the mesh network and the number of relays from itself to all the communication nodes connected to the mesh network,
The communication control means stores the maximum number of relays stored in the communication condition storage means and the number of relays relayed until the reception means receives the data received by the receiving means in the communication condition storage means. The added value obtained by adding the number of relays to the destination is compared, and if the added value is the same as the maximum number of relays, the data is transmitted to the transmission means to the communication node of the destination or the relay destination And when the added value is smaller than the maximum number of relays, the transmission means waits the data for the number of relays obtained by subtracting the added value from the maximum number of relays, and then causes the transmission means to communicate the destination or the relay destination communication node The communication system according to claim 1, wherein the communication system is controlled so as to be transmitted.   When the communication control means is smaller than the maximum number of relays, the communication control means increments the number of relays relayed until reception by the receiving means and from the transmitting means to its own receiving means. The communication system according to claim 2, wherein data is transmitted.   If the added value is the same value as the maximum number of relays, the communication control unit increments the number of relays relayed up to reception by the receiving unit, and transmits the transmission unit to the destination or relay destination. The communication system according to claim 2, wherein data is transmitted. The data includes a transmission time consumed in the communication path until it is received by the receiving means,
In the communication condition storage means, the maximum transmission time in the mesh network and the transmission time from itself to all the communication nodes connected to the mesh network are stored in advance.
The communication condition storage means includes the maximum transmission time stored in the communication condition storage means and the transmission time consumed on the communication path until the reception means receives the data received by the reception means. Is compared with the added value obtained by adding the transmission time to the destination stored in the destination, and when the added value is the same value as the maximum transmission time, the data is sent to the transmission means to the communication of the destination or the relay destination. When the transmission value is smaller than the maximum transmission time, the data is waited for the transmission time obtained by subtracting the addition value from the maximum transmission time, and then the transmission means makes the destination or relay destination The communication system according to claim 1, wherein the communication node is controlled to be transmitted.   When the communication control means is smaller than the maximum transmission time, the communication control means adds a predetermined reference transmission time to the transmission time consumed in the communication path until reception by the receiving means. 6. The communication system according to claim 5, wherein the data is transmitted from a transmission unit to the reception unit of the transmission unit.   When the communication control means has the same value as the maximum transmission time, the transmission control means adds the transmission time to the destination to the transmission time consumed by the communication path until the reception means receives the transmission time. 7. The communication system according to claim 5, wherein the data is transmitted from a transmission unit to a destination or a relay destination.   When the destination determining means determines that the data received by the receiving means is addressed to itself, the destination determining means is based on the communication time elapsed until reception by the receiving means and the maximum communication time stored in the communication condition storing means. The communication system according to claim 1, wherein the communication node includes reception data confirmation means for determining whether or not the data is normal.

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