JP6309267B2 - Communication system and communication node - Google Patents

Description

  The present invention relates to a communication system and a communication node, and more particularly, to a communication system having a plurality of communication nodes and constituting a wireless mesh network, and a communication node constituting the communication system.

  In a mesh network using radio, a method of using a relay node has been considered in order to deliver data to a communication node that does not directly receive radio waves (for example, Patent Document 1). Patent Document 1 is a communication system that uses a relay node when delivering data to an unspecified number of communication nodes, such as broadcast waves, but a communication system that uses a relay node when delivering data to a specific communication node. Is also considered. In such a communication system, there is dynamic routing as a typical method for determining a relay node.

  In this dynamic routing, before starting communication, a communication route is determined by investigating a communication node connected wirelessly to a target communication node. This method can cope with changes in the communication environment because it checks the communication nodes that can communicate immediately before communication, but it calculates and determines the optimal route for the entire network each time communication is performed. There is a problem that the time is very large and it takes time for the data to reach the target communication node.

JP-A-8-8876

  Therefore, an object of the present invention is to provide a communication system that can quickly transmit data to a target node and a communication node that constitutes the communication system.

The invention according to claim 1 for solving the above-described problem is a communication system having a plurality of communication nodes capable of wireless communication and constituting a wireless mesh network, wherein each of the plurality of communication nodes is a data transmission request. Occurs, direct communication means for transmitting direct communication data including the data, addressed to the target node, and originating from the node where the data transmission request is generated, a reception notification means for transmitting a reception notification, and the own node If the direct communication data that is not addressed is received, and then the reception notification cannot be received, the data included in the direct communication data and the direct communication data addressed to the target node including the transmission source of the direct communication data A first proxy communication means for transmitting proxy communication data; and the direct communication upon receiving the reception notification after transmitting the proxy communication data. The first proxy communication completion notification means for transmitting the proxy communication completion notification addressed to the data transmission source, and after detecting the radio wave again after waiting for the back-off time to elapse after the radio wave is not detected for a predetermined time. A communication collision avoiding means for transmitting when there is not, and after receiving the proxy communication data not addressed to the own node, the reception notification is received, and the same proxy communication data as the received proxy communication data is received in the first proxy communication When the means is about to transmit, upon receiving the back-off time extending means for extending the back-off time and the proxy communication completion notification not addressed to its own node, the transmission of the proxy communication data by the first proxy communication means is stopped. Transmission stop means, and when the reception notification means receives the direct communication data addressed to the own node and the proxy communication data, the reception notification means It resides in a communication system, characterized by Shin.

The invention according to claim 2 is a communication system comprising a plurality of communication nodes capable of wireless communication and constituting a wireless mesh network, and each of the plurality of communication nodes includes the data when a data transmission request is generated. Direct communication means for transmitting direct communication data addressed to the target node and originating from the node where the data transmission request occurs, reception notification means for transmitting a reception notification, and receiving the direct communication data not addressed to the own node Then, when the reception notification is not received, the proxy communication data addressed to the target node of the direct communication data including the data included in the direct communication data and the transmission source of the direct communication data is transmitted. When the reception notification is received after transmitting the proxy communication data with the proxy communication means, the proxy communication addressed to the transmission source of the direct communication data A first proxy communication completion notification means for transmitting completion notification, receives the proxy communication data is not addressed to the own node, then, if it can not receive the reception notification, as a transmission destination the destination of the proxy communication data a second proxy communication unit configured to transmit the proxy communication data, receiving the proxy communication completion notification is not addressed to the own node, then, if unable to receive the reception notification, the destination the destination of the proxy communication completion notice A second proxy communication completion notification means for transmitting the proxy communication completion notification, wherein the reception notification means receives the direct communication data addressed to the own node, the proxy communication data, and the proxy communication completion notification. The communication system is characterized by transmitting the reception notification.

According to a third aspect of the present invention, the first proxy communication unit and the second proxy communication unit transmit the proxy communication data obtained by adding the own node to a proxy communication list representing a relay node of the proxy communication data, and The first proxy communication completion notification means obtains a node that has transmitted proxy communication data before its own node from the proxy communication list of the transmitted proxy communication data, and the proxy communication completion notification with the obtained node as a relay destination node When the second proxy communication completion notification means receives the proxy communication completion notification whose relay destination node is its own node, the second proxy communication completion notification means before the local node from the proxy communication list of the received proxy communication completion notification The proxy communication completion notification is transmitted to the node that has transmitted the proxy communication data, and the proxy communication completion notification is transmitted with the determined node as the relay destination node. When receiving the notification, upon receiving the reception notification of the proxy communication completion notification from the relay destination node resides in the communication system according to claim 2, characterized in that stops the transmission of the proxy communication completion notification.

According to a fourth aspect of the present invention, when a data transmission request is generated in a communication node that constitutes a wireless mesh network, the data is directly included in the destination node and the node where the data transmission request is generated. Included in the direct communication data if the direct communication means for transmitting communication data, the reception notification means for transmitting a reception notification, and the direct communication data that is not addressed to its own node are received and then the reception notification cannot be received. A first proxy communication means for transmitting proxy communication data addressed to a target node of the direct communication data including the data to be transmitted and a source of the direct communication data, and receiving the reception notification after transmitting the proxy communication data A first proxy communication completion notification means for transmitting a proxy communication completion notification addressed to the transmission source of the direct communication data, and no radio wave is detected A communication collision avoidance means for transmitting when the radio wave is not detected again after waiting for the back-off time to elapse after the state continues for a predetermined time; and after receiving the proxy communication data not addressed to the own node, the reception When the notification is received and the first proxy communication means is to transmit the same proxy communication data as received, the back-off time extending means for extending the back-off time and the proxy not addressed to the own node A transmission stop unit that stops transmission of the proxy communication data by the first proxy communication unit when receiving a communication completion notification, the reception notification unit including the direct communication data addressed to the own node and the proxy communication data In the communication node, the reception notification is transmitted when the message is received.

According to the fifth aspect of the present invention, when a data transmission request is generated in a communication node constituting a wireless mesh network, the communication node directly includes the data and is directed to the destination node and the node where the data transmission request is generated. Included in the direct communication data if the direct communication means for transmitting communication data, the reception notification means for transmitting a reception notification, and the direct communication data that is not addressed to its own node are received and then the reception notification cannot be received. A first proxy communication means for transmitting proxy communication data addressed to a target node of the direct communication data including the data to be transmitted and a source of the direct communication data, and receiving the reception notification after transmitting the proxy communication data A first proxy communication completion notification means for transmitting a proxy communication completion notification addressed to the transmission source of the direct communication data, and the proxy not addressed to the own node. Receiving communication data, then, if unable to receive the reception notification, and the second proxy communication unit configured to transmit the proxy communication data of which destination is the destination of the proxy communication data, not addressed to the own node the proxy A second proxy communication completion notification means for transmitting a proxy communication completion notification whose destination is the transmission destination of the proxy communication completion notification when the communication completion notification is received and then the reception notification cannot be received. The reception notification means resides in a communication node that transmits the reception notification when receiving the direct communication data addressed to the own node, the proxy communication data, and the proxy communication completion notification.

As described above, according to the first , second, fourth, and fifth aspects of the present invention, the relay route is determined while transmitting data to the target node. Data can be sent quickly.

According to the first aspect of the present invention, after receiving proxy communication data not addressed to the own node, receiving a reception notification, and the first proxy communication means trying to transmit the same proxy communication data as received Since the back-off time is extended, the proxy communication completion notification is transmitted with priority over the proxy communication data. If a proxy communication completion notification that is not addressed to the own node is received, it is not necessary to perform proxy communication, and transmission of proxy communication data is stopped. Thereby, it is possible to perform data communication even more quickly without wastefully transmitting proxy communication data. In addition, if the node that sent the proxy communication data cannot receive the reception notification from the target node due to a communication failure, etc., and if the proxy communication completion notification is not sent even after the extended backoff time has passed, Proxy communication data and proxy communication completion notification can be transmitted from the node. In addition, if the proxy communication completion notification cannot be received from the node that transmitted the proxy communication data, the proxy completion notification is not immediately transmitted from the other nodes, and the reception notification is received after the proxy communication data is once transmitted. By transmitting the proxy completion notification after this, it is possible to prevent a plurality of other nodes from entering a state of attempting to transmit the proxy communication completion notification.

According to the second aspect of the present invention, the proxy communication data and the proxy communication completion notification can also be transmitted through a plurality of nodes.

According to the third aspect of the present invention, if the communication state does not change between when proxy communication data is transmitted and when a proxy communication completion notification is returned, the proxy communication data is relayed via the relay destination node. The communication completion notification can be transmitted to the transmission source node, and the proxy communication completion notification is not transmitted from a node that is not the relay communication node of the proxy communication data. In addition, after sending proxy communication data, if any failure occurs on the route of proxy communication data, since reception notification cannot be received, proxy communication completion notification may be sent by relaying a node that is not a relay destination node. it can.

It is a block diagram which shows the communication system of this invention in 1st Embodiment. It is a figure which shows the frame structure of the direct communication data in 1st Embodiment, proxy communication data, and a proxy communication completion notification. It is a block diagram which shows the structure of the communication node shown in FIG. 1 in 1st Embodiment. It is a flowchart which shows the transmission processing procedure of the microcomputer shown in FIG. It is a flowchart which shows the reception processing procedure of the microcomputer shown in FIG. 3 in 1st Embodiment. It is a sequence diagram for demonstrating operation | movement of the communication system shown in FIG. It is a sequence diagram for demonstrating operation | movement of the communication system shown in FIG. It is a sequence diagram for demonstrating operation | movement of the communication system shown in FIG. It is the figure which put together the operation | movement of each node when the direct communication data in 2nd Embodiment, proxy communication data, and proxy communication completion notification were received. It is a block diagram which shows the structure of the communication node in 2nd Embodiment. It is a flowchart which shows the reception processing procedure of the microcomputer shown in FIG. 3 in 2nd Embodiment. It is a flowchart which shows the timer processing procedure of the microcomputer shown in FIG. 3 in 2nd Embodiment. It is a block diagram which shows the communication system of this invention in 2nd Embodiment. FIG. 13 is a sequence diagram for explaining the operation of the communication system shown in FIG. 12. It is a block diagram which shows the communication system of this invention in 3rd Embodiment. It is a figure which shows the frame structure of the direct communication data in 3rd Embodiment, proxy communication data, and proxy communication completion notification. It is a block diagram which shows the structure of the communication node in 3rd Embodiment. It is a flowchart which shows the reception processing procedure of the microcomputer shown in FIG. 3 in 3rd Embodiment. FIG. 16 is a sequence diagram for explaining the operation of the communication system shown in FIG. 15.

First Embodiment Hereinafter, a communication system according to the present invention will be described with reference to FIGS. As shown in FIG. 1, the communication system 1 according to the present invention includes a plurality of communication nodes 20 (node A, node B, node C, and node D), and these nodes A to D are wireless mesh networks. Is configured.

  In the communication system 1 shown in FIG. 1, the node A is arranged so as to be able to wirelessly communicate with the nodes B and C. Node B is arranged to be able to communicate with nodes A, C, and D by radio. Node C is arranged so as to be able to communicate with nodes A, B, and D in a wireless manner. The node D is arranged so as to be able to wirelessly communicate with the nodes B and C.

  These nodes A to D exchange signals such as direct communication data, ACK (= reception notification) / NCK, proxy communication data, and proxy communication completion notification. The direct communication data is transmitted from the nodes A to D that have requested transmission of data. The ACK is transmitted from the nodes A to D that have normally received direct communication addressed to the own node, proxy communication data, or proxy communication completion notification. The NCK is transmitted from the nodes A to D that could not normally receive direct communication, proxy communication data, or proxy communication completion notification addressed to the own node.

  The proxy communication data is transmitted from the nodes A to D that receive direct communication data not addressed to the own node and cannot receive ACK within a predetermined time or receive NCK. The proxy communication data includes data in the received direct communication data that is not addressed to the own node. The proxy communication completion notification is transmitted from the nodes A to D that have received the ACK after transmitting the proxy communication data.

  The frame configuration of the direct communication data, proxy communication data, and proxy communication completion notification is as shown in FIG. The source address As2 stores the address of the node where the data transmission request has occurred, and the destination address Ar2 stores the address of the target node for data transmission. The transmission source address As1 and the transmission destination address Ar1 store the addresses of the actual transmission source and transmission destination nodes.

  That is, in the direct communication data, the address of the node where the data transmission request is generated is stored in the transmission source address As1, and the address of the target node is stored in the transmission destination address Ar1. In the proxy communication data, the transmission source address As1 stores the address of the transmission node of the proxy communication data, and the transmission destination address Ar1 stores the address of the target node. In the proxy communication completion notification, the transmission source address As1 stores the address of the transmission node of the proxy communication completion notification, and the transmission destination address Ar1 stores the address of the node where the data transmission request has occurred.

  The communication type S stores a direct communication marker indicating direct communication data, a proxy communication marker indicating proxy communication data, and a proxy communication completion notification marker indicating proxy communication completion notification. . Data D stores data generated from the application. The error check code stores a check code such as a CRC code for confirming the normality of the communication frame.

  Next, the configuration of the communication node 20 will be described below with reference to FIG. As shown in the figure, the communication node 20 includes an antenna AT for performing wireless communication with another communication node 20, a direct communication buffer 21, a proxy communication buffer 22, a proxy communication completion notification buffer 23, a communication node 20 and a microcomputer (hereinafter referred to as a microcomputer) 24 for controlling the entire system.

  The direct communication buffer 21 is a buffer in which direct communication data is temporarily stored. The proxy communication buffer 22 is a buffer in which proxy communication data is temporarily stored. The proxy communication completion notification buffer 23 is a buffer in which proxy communication completion notification is temporarily stored.

  The microcomputer 24 is configured by a CPU (Central Processing Unit) having a memory such as a RAM (Randam Access Memory) and a ROM (Read Only Memory). The microcomputer 24 includes a communication unit 24A, an interface (hereinafter referred to as I / F) 24B, a direct communication data creation function 24C, a destination determination function 24D, a communication type determination function 24E, a proxy communication data generation function 24F, and proxy communication. A completion notification creation function 24G, a buffer confirmation function 24H, a transmission request function 24I, an ACK presence / absence confirmation function 24J, and a backoff extension function 24K are provided.

  The communication unit 24A controls the antenna AT to transmit and receive signals. The I / F 24B is an interface for connecting to an application. When a data transmission request is generated from an application, the direct communication data creation function 24C creates direct communication data including the data and stores it directly in the communication buffer 21.

  The destination discriminating function 24D discriminates the destination of the signal received by the antenna AT. The communication type determination function 24E determines the type of signal received by the antenna AT. Specifically, the communication type determination function 24E determines whether the received signal is direct communication data, proxy communication data, communication completion notification, ACK, or NCK.

  The proxy communication data creation function 24F receives direct communication data not addressed to its own node, and then receives the direct communication data when it cannot receive the ACK (that is, it cannot receive the ACK within a predetermined time or receives the NCK). Proxy communication data including data included in the communication data is stored in the proxy communication buffer 22.

  When the proxy communication completion notification creation function 24G receives the ACK after transmitting the proxy communication data, the proxy communication completion notification creation function 24G creates a proxy communication completion notification and stores it in the proxy communication completion notification buffer 23. The buffer confirmation function 24H confirms the state of each of the buffers 21 to 23, and determines whether or not proxy communication data or a proxy communication completion notification is stored in each buffer. The transmission request function 24I sends a transmission request for direct or proxy communication data or communication completion notification in the buffers 21 to 23 determined to be stored by the buffer confirmation function 24H to the communication unit 24A for wireless transmission.

  The communication unit 24A has a communication collision avoidance function 24A1 as communication collision avoidance means. The communication collision avoidance function 24A1 performs so-called CSMA / CA processing, and does not transmit immediately when there is a transmission request from the transmission request function 24I so that communication between the nodes A to D does not collide. It waits for a predetermined period of time in which no is detected. Further, the communication collision avoidance function 24A1 performs transmission only when no radio wave is detected before the back-off time elapses. The backoff time is set to a random time. However, the back-off time when sending an ACK is set to a minimum (for example, 0) so that it can be transmitted preferentially. Further, the back-off time when directly retransmitting the communication data is set to the maximum, and the priority is the lowest.

  The AKC presence / absence confirmation function 24J confirms whether or not an ACK has been received after receiving proxy communication data not addressed to its own node. When the backoff extension function 24K receives the ACK by the AKC presence / absence confirmation function 24J and has the same proxy communication data as the proxy communication data not addressed to the own node in the proxy communication buffer 22, the backoff extension function 24K sets the backoff time. Extend.

  Next, operation | movement of the communication system 1 mentioned above is demonstrated below with reference to FIG. The microcomputer 24 executes the transmission process shown in FIG. 4 in response to power-on. In the transmission process, the microcomputer 24 first determines whether or not there is a data transmission request from the application (step S1). If there is a data transmission request (Y in step S1), the microcomputer 24 takes in data from the application and stores it directly in the data D (see FIG. 2) of the communication buffer 21 (step S2).

  Further, the microcomputer 24 stores the address of its own node in the transmission source addresses As1 and As2 of the direct communication buffer 21, the address of the target mode in the transmission destination addresses Ar1 and Ar2, and the direct communication marker in the communication type S ( Step S3). As a result, the direct communication buffer 21 stores the direct communication data having the frame configuration shown in FIG.

  Thereafter, the microcomputer 24 functions as a direct communication means and transmits the direct communication data stored in the direct communication buffer 21 (step S4). Thereafter, when the microcomputer 24 receives an ACK within a predetermined time (Y in step S5), the microcomputer 24 determines that the communication is successful, directly clears the communication buffer 21 (step S8), and then returns to step S1 again. In contrast, when the microcomputer 24 cannot receive ACK within a predetermined time or receives NCK (N in step S5), the microcomputer 24 counts up a retransmission counter (step S6). Thereafter, if the retransmission counter is equal to or smaller than the predetermined number of times (N in Step S7), the microcomputer 24 immediately returns to Step S1.

  If the process returns to step S1 without clearing the direct communication buffer 21, direct communication data is stored in the direct communication buffer 21. Therefore, the microcomputer 24 determines that the direct communication data is stored in the direct communication buffer 21 (Y in step S9), and proceeds to step S4. By this step S4, the direct communication data is retransmitted. As a result of repeating steps S4 to S6, when the retransmission counter exceeds the predetermined number (Y in step S7), the microcomputer 24 directly clears the communication buffer 21 as a communication failure (step S8), and returns to step S1.

  Further, when the proxy communication data is stored in the proxy communication buffer 22 (Y in Step S10), the microcomputer 24 functions as a first proxy communication means and transmits the proxy communication data (Step S11). If the microcomputer 24 cannot receive ACK within a predetermined time or receives NCK (N in step S12), the microcomputer 24 determines that communication has failed, clears the proxy communication buffer 22 (step S13), and returns to step S1.

  On the other hand, when receiving an ACK within a predetermined time (Y in step S12), the microcomputer 24 stores a proxy communication completion notification in the proxy communication completion notification buffer 23 (step S14).

  Specifically, in step S14, the microcomputer 24 sends the address of its own node to the source address As1 of the proxy communication completion notification buffer 23, the source address As2 of proxy communication data to the destination address Ar1 and the source address As2 (= data transmission request). Node address), the address of the proxy communication data destination address Ar2 (= target node) is stored in the destination address Ar2, the proxy communication completion notification marker is stored in the communication type S, and the data D of the proxy communication data is stored in the data D To do. As a result, the proxy communication completion notification buffer 23 stores the proxy communication completion notification having the frame configuration shown in FIG.

  If the proxy communication completion notification is stored in the proxy communication completion notification buffer 23 when returning to step S1 (Y in step S15), the microcomputer 24 functions as a first proxy communication completion notification means, and performs proxy communication completion notification. The proxy communication completion notification stored in the buffer 23 is transmitted (step S16). After that, when receiving an ACK within a predetermined time (Y in Step S17), the microcomputer 24 determines that the communication is successful, clears the proxy communication buffer 22 and the proxy communication completion notification buffer 23 (Step S20), and performs Step S1. Return to.

  On the other hand, when the microcomputer 24 cannot receive ACK within a predetermined time or receives NCK (N in step S17), the microcomputer 24 increments the retransmission counter (step S18). Thereafter, if the retransmission counter is equal to or smaller than the predetermined number of times (N in Step S19), the microcomputer 24 immediately returns to Step S1.

  If the proxy communication completion notification buffer 23 is not cleared and the process returns to step S1, the proxy communication completion notification buffer 23 is in a state where communication data is stored directly. Therefore, the microcomputer 24 determines that the proxy communication completion notification is stored in the proxy communication completion notification buffer 23 (Y in step S15), and proceeds to step S16. By this step S16, the proxy communication completion notification is retransmitted. As a result of repeating steps S16 to S18, if the retransmission counter exceeds a predetermined number (Y in step S19), the microcomputer 24 clears the proxy communication buffer 22 and the proxy communication completion notification buffer 23 as communication failure (step S20). ), The process returns to step S1.

  The microcomputer 24 performs a reception process in parallel with the transmission process. Next, the reception process of the microcomputer 24 will be described with reference to FIG. When the microcomputer 24 receives from the antenna AT a signal whose ACK / NCK or source address As2 is other than the data of its own node, the microcomputer 24 starts reception processing. In the reception process, the microcomputer 24 determines whether or not the destination of the received signal (transmission destination address Ar1) is addressed to its own node (step S21).

  If it is addressed to its own node (Y in step S21), the microcomputer 24 determines whether or not the received signal is direct communication data or proxy communication data (step S22). If it is direct communication data or proxy communication data (Y in step S22), the microcomputer 24 determines whether or not the data has been normally received from the error check code (step S23).

  If the data can be normally received (Y in step S23), the microcomputer 24 functions as a reception notifying unit, transmits ACK and outputs the data to the application (step S24), and ends the reception process. On the other hand, if the data cannot be received normally (N in step S23), the microcomputer 24 transmits NCK (step S25) and ends the reception process.

  If it is not direct communication data or proxy communication data (N in step S22), the microcomputer 24 determines whether it is a proxy communication completion notification (step S26). If it is a proxy communication completion notification (Y in step S26), the microcomputer 24 determines that the communication is successful, transmits ACK and clears the communication buffer 21 directly (step S27), and then ends the reception process. If it is not a proxy communication completion notification (N in step S26), the microcomputer 24 ends the reception process without doing anything.

  If the received signal is not addressed to the own node (N in step S21), the microcomputer 24 determines whether or not it is direct communication data (step S28). If it is direct communication data (Y in step S28), and if ACK is received within a predetermined time (Y in step S29), the microcomputer 24 determines that the communication is successful and ends the reception process without doing anything. . On the other hand, if there is no ACK within a predetermined time or NCK is received (N in step S29), the microcomputer 24 creates proxy communication data and stores it in the proxy communication buffer 22 (step S30). The reception process ends.

  More specifically, in step S30, the microcomputer 24 sends its own node address as the transmission source address As1 of the proxy communication buffer 22, direct transmission data source address As2 (= address of the data transmission request node), transmission destination address as the transmission source address As2. The destination address Ar2 (= address of the target node) of direct communication data is stored in Ar1 and Ar2, the proxy communication marker is stored in communication type S, and the data D of direct communication data is stored in data D. As a result, the proxy communication buffer 22 stores the proxy communication data having the frame configuration shown in FIG.

  On the other hand, if it is not direct communication data (N in step S28), the microcomputer 24 determines whether or not the received signal is proxy communication data (step S31). If the microcomputer 24 is proxy communication data (Y in step S31), then the proxy communication data having the same data D as the proxy communication data received by the proxy communication buffer 22 is received within the predetermined time. If it is stored (Y in step 32), it functions as a back-off time extending means, and after extending the back-off time (step S33), the reception process is terminated. On the other hand, when the microcomputer 24 cannot receive ACK within a predetermined time or receives NCK (N in step S32), the microcomputer 24 ends the receiving process without doing anything.

  If the microcomputer 24 is neither direct communication data nor proxy communication data (N in step S31), the microcomputer 24 then determines whether it is a proxy communication completion notification (step S34). If it is a proxy communication completion notification (Y in step S34), the microcomputer 24 determines whether or not the same data is stored in the data D of the received proxy communication completion notification and the proxy communication data stored in the proxy communication buffer 22. Is determined (step S35).

  If the same data is stored (Y in step S35), the microcomputer 24 determines that the communication is successful, acts as a transmission stop unit, clears the proxy communication buffer 22, and stops transmitting proxy communication data ( Step S36), the reception process is terminated. On the other hand, if the same data is not stored (N in step S35), the microcomputer 24 ends the reception process without doing anything. If the received signal not addressed to the own node is not direct communication data, proxy communication data, or proxy communication completion notification (N in step S34), the microcomputer 24 ends the reception process without doing anything.

  Next, the operation of the communication system 1 described above will be described below with reference to the sequences of FIGS. First, the operation of the communication system when a data transmission request from the node A to the node B occurs will be described with reference to FIG. In the following description, the operations performed by the nodes A to D are actually executed by the microcomputer 24 of the nodes A to D.

  When a data communication request to node B occurs at node A, node A creates direct communication data with source addresses As1 and As2 as node A, destination addresses Ar1 and Ar2 as node B, and type as direct communication. And transmit from the antenna AT.

  Direct communication data from node A is received by node B and node C. When the node B receives the direct communication data addressed to itself, the node B transmits an ACK indicating that it has been received. The ACK from node B is received by node A and node C. When the node A receives the ACK from the node B, the node A determines that the communication is successful, clears the direct communication buffer 21 and stops the retransmission of the direct communication data. When node C receives ACK from node B after receiving direct communication data not addressed to itself, node C does nothing.

  Next, the operation of the communication system when a data transmission request from the node A to the node D occurs will be described with reference to FIG. When a data transmission request to node D occurs at node A, node A creates direct communication data with source addresses As1 and As2 as node A, destination addresses Ar1 and Ar2 as node D, and type as direct communication. And transmit from the antenna AT.

  Direct communication data from node A cannot be received by node D, but is received by node B and node C. When the node B and the node C receive direct communication data not addressed to the own node and cannot receive the AKC thereafter, the source address As1 is the node B and C, the source address As2 is the node A, and the destination addresses Ar1 and Ar2 The proxy communication data with the node D and the type as the proxy communication is created and stored in the proxy communication buffer 22. At this time, the node B and the node C try to transmit the proxy communication data, and the node A tries to retransmit the communication data directly.

  As described above, the back-off time for retransmission of direct communication data is set to the longest time. At this time, if the back-off time of node B is shorter than the back-off time of node C, node B obtains the transmission right, node B transmits proxy communication data, and nodes A and C suspend transmission. Of course, if the backoff time of the node C is shorter than the backoff time of the node B, the node C obtains the transmission right. Here, an example in which the node B obtains the transmission right will be described.

  Proxy communication data from node B is received by node A, node C, and node D. Node A does nothing particularly because the source address As2 of the proxy communication data is the address of its own node. When node D receives proxy communication data addressed to itself, node D attempts to transmit ACK. That is, at this time, the node A tries to retransmit the communication data directly, the node C tries to send the proxy communication data, and the node D tries to send the ACK. Since the ACK back-off time is set to the shortest, the node D obtains the transmission right, and the ACK is transmitted from the node D.

  The ACK from node D is received by node B and node C. When the node B receives the ACK, the node B tries to transmit a proxy communication completion notification with the source address As1 as the node B, the destination address Ar1 and the source address As2 as the node A, and the destination address Ar2 as the node D. When node C receives ACK after receiving proxy communication data from node B, node C extends the back-off time. That is, at this time, the node A tries to retransmit the communication data directly, the node B tries to send the proxy communication completion notification, and the node C tries to send the proxy communication data.

  As described above, since the back-off time of the node C is extended, the node B obtains the transmission right again and transmits the proxy communication completion notification. When the node B proxy communication completion notification arrives at the node A, the node A transmits an ACK and clears the direct communication buffer 21 to stop the direct communication data retransmission. When receiving the proxy communication completion notification, the node C clears the proxy communication buffer 22 and stops transmitting proxy communication data. When the node B receives the ACK from the node A, the node B clears the proxy communication buffer 22 and the proxy communication completion notification buffer 23 and stops resending the proxy communication completion notification.

  Next, the operation of the communication system when a data transmission request from the node A to the node D occurs when a failure occurs in the communication from the node B to the node D will be described with reference to FIG. Since the node A obtains the transmission right and transmits the proxy communication data after the data transmission request to the node D is generated, the description is omitted.

  Proxy communication data from node B cannot be received by node D, but is received by node A and node C. Node A does nothing particularly because the source address As2 of the proxy communication data is the address of its own node. Node C does not extend the back-off time if it does not receive ACK after receiving proxy communication data. Further, since the node B cannot receive the ACK after transmitting the proxy communication data, the node B clears the proxy communication data. At this time, the node A is in a state of attempting to directly retransmit communication data, and the node C is in a state of attempting to transmit proxy communication data.

  As described above, since the back-off time of node C is not extended, node C obtains a transmission right and transmits proxy communication data. Proxy communication data from node C is received by node A, node B, and node D. Node A does nothing particularly because the source address As2 of the proxy communication data is the address of its own node. When node D receives proxy communication data addressed to itself, node D transmits ACK.

  The ACK from node D is received by node C. When the node C receives the ACK, the node C transmits a proxy communication completion notification with the source address As1 as the node C, the destination address Ar1 and the source address As2 as the node A, and the destination address Ar2 as the node D. When the node C's proxy communication completion notification arrives at the node A, the node A transmits an ACK and stops the retransmission of the communication data directly. When the node C receives the proxy communication completion notification, the node C discards the proxy communication data and stops transmitting the proxy communication data.

  According to the above-described embodiment, each of the nodes A to D transmits direct communication data including data to the destination node when a data transmission request to the destination node is generated. When direct or proxy communication data addressed to the own node is received, an ACK indicating that it has been received is transmitted. Further, when direct communication data not addressed to the own node is received, and then ACK cannot be received, proxy communication data including data included in the direct communication data is transmitted. Further, when the ACK is received after the proxy communication data is transmitted, the proxy communication completion notification is directly transmitted to the transmission source of the communication data. Thereby, since the relay route is determined while transmitting data to the target node, it is not necessary to determine the route in advance, and the data can be quickly transmitted to the target node.

  In addition, according to the above-described embodiment, when each of the nodes A to D receives proxy communication data not addressed to itself, receives an ACK, and attempts to transmit the same proxy communication data received Since the back-off time is extended, the proxy communication completion notification is transmitted with priority over the proxy communication data. If the proxy communication completion notification is received, the proxy communication does not need to be performed, and the transmission of the proxy communication data is stopped. Thereby, it is possible to perform data communication even more quickly without wastefully transmitting proxy communication data. In addition, when the node B that has transmitted the proxy communication data due to a communication failure cannot receive the reception notification from the target node D and the extended back-off time has elapsed, the proxy communication completion notification is not transmitted. Proxy communication data and proxy communication completion notification can be transmitted from another node C.

  In addition, when the proxy communication completion notification cannot be received from the node B that transmitted the proxy communication data, the proxy completion notification is not immediately transmitted from the other node C, and the ACK is once received after the proxy communication data is transmitted. After receiving, a proxy completion notification is sent. If the proxy completion notification is transmitted immediately, when there are a plurality of other nodes, the proxy communication completion notification is transmitted from the plurality of other nodes. Further, since the proxy communication completion notification is a communication for informing the transmission source node A that the data communication has been successfully performed, retry is permitted. There is a risk that a proxy communication completion notification may be sent by retry.

  On the other hand, in this embodiment, the transmission timing of the proxy communication completion notification is set only when the proxy communication is successful (ACK reception). As a result, among the plurality of other nodes, the first node that has obtained the right to transmit proxy communication data is preferentially transmitted the notification of proxy communication completion, and otherwise the transmission is postponed because the back-off time is extended. The Thereby, the proxy communication completion notification is not transmitted unnecessarily.

  Note that, according to the above-described embodiment, when each of the nodes A to D receives proxy communication data not addressed to itself and then receives an ACK, the back-off time has been extended, but the proxy communication buffer 22 immediately. May be cleared.

Second Embodiment Hereinafter, a communication system 1 according to a second embodiment of the present invention will be described with reference to FIGS. In the first embodiment, only the direct communication data is communicated on behalf of other nodes, but in the second embodiment, this is expanded to the proxy communication data and the proxy communication completion notification. It also relays proxy communication data and proxy communication completion notifications.

  Since the frame configurations of the direct communication data, the proxy communication data, and the proxy communication completion notification are the same as those in the first embodiment, detailed description thereof is omitted here.

  In the second embodiment, each of the nodes A to D performs the operation shown in FIG. 9 when receiving the direct communication data, the proxy communication data, and the proxy communication completion notification described above. First, a case where each node A to D receives direct communication data that is not addressed to its own node (= the destination address Ar1 is not its own node) will be described. After that, each node A to D stores the proxy communication data including the data D in the direct communication data in the proxy communication buffer 22 when ACK cannot be received within a predetermined time. Thereby, the proxy communication data is transmitted in the next transmission process.

  However, when the proxy communication data having the same data D as the received direct communication data D and the proxy communication completion notification are already stored in the buffers 22 and 23, the nodes A to D receive the direct communication data. But nothing is done. Thereby, the proxy communication data and proxy communication completion data stored in the buffers 22 and 23 in the next transmission process are transmitted.

  Further, each node A to D does nothing particularly when receiving direct communication data not addressed to itself and receiving ACK within a predetermined time thereafter.

  Next, a case where the nodes A to D receive proxy communication data not addressed to the own node will be described. At this time, if the ACK cannot be received within a predetermined time, the nodes A to D store in the proxy communication buffer 22 new proxy communication data in which the source address As1 of the proxy communication data is rewritten to the address of the own node. Thereby, the proxy communication data is transmitted in the next transmission process.

  However, when the proxy communication data having the same data D as the received proxy communication data D and the proxy communication completion notification are already stored in the buffers 22 and 23, the nodes A to D receive the proxy communication data. But nothing is done. Thereby, the proxy communication data and the proxy communication completion notification stored in the buffer in the next transmission process are transmitted.

  On the other hand, if the ACK is received within the predetermined time, the nodes A to D extend the back-off time if the proxy communication data having the same data D is stored in the proxy communication buffer 22. The transmission of proxy communication data is delayed. On the other hand, when proxy communication completion notification is stored, nothing is done even when proxy communication data is received. As a result, the proxy communication completion notification stored in the buffer 23 is transmitted in the next transmission process. If neither proxy communication data nor proxy communication completion notification is stored, nothing is done.

  Next, a case will be described in which the nodes A to D receive a proxy communication completion notification that is not addressed to their own node, and then cannot receive an ACK within a predetermined time. At this time, when proxy communication data having the same data D as the received proxy communication completion notification data D is stored, the nodes A to D discard (clear) the proxy communication data and receive the received proxy A new proxy communication completion notification in which the transmission source address As1 of the communication completion notification is rewritten to the address of the own node is stored in the proxy communication completion notification buffer 23. Thereby, the proxy communication completion notification is transmitted in the next transmission process.

  Further, when the proxy communication completion notification having the same data D as the received proxy communication completion notification data D is already stored in the buffer 23, the nodes A to D do nothing in particular. When neither proxy communication data nor proxy communication completion notification is stored, the nodes A to D store the proxy communication completion notification in the proxy communication completion notification buffer 23. Thereby, the proxy communication completion notification is transmitted in the next transmission process.

  Next, a case where the nodes A to D receive a proxy communication completion notification not addressed to the own node and then receive an ACK within a predetermined time will be described. At this time, when proxy communication data having the same data D as the received proxy communication completion notification and proxy communication completion notification are stored, the nodes A to D discard the proxy communication data and proxy communication completion.

  The proxy communication data and the proxy communication completion notification stored in the buffers 22 and 23 at this time are stored in the respective buffers 22 and 23 after the first predetermined time Tw1 (seconds) since the storage, regardless of the communication status and result. The proxy communication completion notification is not used. In addition, after the first predetermined time Tw1 has elapsed and until the second predetermined time Tw2 (seconds) has elapsed, a proxy communication data that is no longer used or a signal having the same data D as the proxy communication completion notification is received. Ignore it.

  Next, the configuration of the communication node in the second embodiment will be described below with reference to FIG. In the figure, the same components as those shown in FIG. 3 already described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. As shown in the figure, in addition to the functions 24C to 24K described in the first embodiment, the microcomputer 24 further includes a time measurement management function 24L, a buffer status confirmation function 24M, a proxy communication completion notification creation function 24N, It has.

  The time measurement management function 24L measures and manages the elapsed time since the proxy communication data and the proxy communication completion notification are stored in the buffers 22 and 23. The buffer status confirmation function 24M confirms the status of each of the buffers 21 to 23 and determines whether or not proxy communication data or a proxy communication completion notification is stored directly or in each of them. The proxy communication completion notification creation function 24N receives a proxy communication completion notification that is not addressed to its own node, and thereafter cannot receive an ACK, and if there is no proxy communication completion notification that is the same as the received proxy communication completion notification, proxy communication A completion notification is created and stored in the proxy communication completion notification buffer 23.

  In addition to the operation in the first embodiment, the proxy communication data creation function 24F receives proxy communication data that is not addressed to its own node, and thereafter cannot receive an ACK and is the same as the received proxy communication data. If neither the proxy communication data having the data D nor the proxy communication completion notification is stored, the proxy communication data including the data D included in the received proxy communication data is stored in the proxy communication buffer 22.

  Next, the operation of the communication system 1 described above will be described. The microcomputer 24 executes transmission processing and reception processing in response to power-on. Note that the transmission process in the second embodiment is the same as the transmission process shown in FIG. 4 described in the first embodiment, and therefore detailed description thereof is omitted here.

  The reception process of the microcomputer 24 described above will be described with reference to FIG. In FIG. 11, the same parts as those described in the first embodiment with reference to FIG. 5 are denoted by the same reference numerals, and detailed description thereof is omitted. That is, the microcomputer 24 also functions as a second proxy communication unit in step S11, and also functions as a second proxy communication completion history unit in step S16.

  First, when the microcomputer 24 receives a signal other than the ACK / NCK and the source address As2 other than the data of its own node from the antenna AT, the microcomputer 24 starts reception processing. In the reception process, the microcomputer 24 determines whether or not the destination of the received signal (transmission destination address Ar1) is addressed to its own node (step S21).

  If it is addressed to its own node (Y in step S21), the microcomputer 24 performs steps S22 to S27 as in the first embodiment. If the received signal is not addressed to the own node (N in step S21), the microcomputer 24 determines whether or not the timer T1 that counts the first predetermined time Tw1 is operating (step S40).

  If the timer T1 is in operation (Y in step S40), the microcomputer 24 determines that the first predetermined time Tw1 has not elapsed since the proxy communication data and the proxy communication completion notification are stored in the buffers 22 and 23. Then, the process proceeds to step S28. On the other hand, if the timer T1 is not in operation (N in step S40), the microcomputer 24 determines whether or not the timer T2 for counting the second predetermined time Tw2 is in operation (step S41).

  If the timer T2 is in operation (Y in step S41), it is after the first predetermined time Tw1 has elapsed and thereafter the second predetermined time Tw2 has not elapsed. At this time, the microcomputer 24 compares the data D of the proxy communication data or the proxy communication completion notification data stored in the buffers 22 and 23 with the data D of the received signal. As a result of the comparison, if they are the same (Y in step S42), the reception process is terminated and the received signal is ignored. If they are not the same (N in step S42), the process proceeds to step S28.

  In step S28, the microcomputer 24 determines whether or not the received signal is direct communication data (step S28). If the data is direct communication data (Y in step S28), and if there is an ACK within a predetermined time (Y in step S29), the microcomputer 24 determines that the communication is successful and ends the reception process without doing anything. . On the other hand, if there is no ACK within a predetermined time or NCK is received (N in step S29), the microcomputer 24 receives proxy communication data or proxy having the same data D as the received direct communication data D It is determined whether or not a communication completion notification is stored in the buffers 22 and 23 (step S43).

  If proxy communication data having the same data D or proxy communication completion notification is stored (Y in step S43), the microcomputer 24 ends the reception process. On the other hand, if the proxy communication data having the same data D or the proxy communication completion notification is not stored (N in step S43), the microcomputer 24 creates the proxy communication data and stores it in the proxy communication buffer 22 (Step S30) After starting the timer T1 that counts the first predetermined time Tw1 (Step S44), the reception process is terminated.

  If the received signal is not direct communication data (N in step S28), the microcomputer 24 determines whether it is proxy communication data (step S31). If it is proxy communication data (Y in step S31), the microcomputer 24 then determines whether or not there is an ACK within a predetermined time (step S45). If there is an ACK within the predetermined time (Y in step S45), the microcomputer 24 stores proxy communication data having the same data D as the received proxy communication data in the proxy communication buffer 22 (Y in step S46). ) After extending the back-off time (step S33), the reception process is terminated. If proxy communication data having the same data D is not stored (N in step S46), the microcomputer 24 immediately ends the reception process.

  On the other hand, when the microcomputer 24 cannot receive ACK within a predetermined time or receives NCK (N in step S45), the proxy communication data having the same data D as the received proxy communication data D is received. Alternatively, it is determined whether or not the proxy communication completion notification is stored in the buffers 22 and 23 (step S47). If proxy communication data having the same data D and a proxy communication completion notification are stored (Y in step S47), the microcomputer 24 ends the reception process.

  On the other hand, if proxy communication data and proxy communication completion notification are not stored (N in step S47), the microcomputer 24 renews the source address As1 of the received proxy communication data with the address of its own node. The proxy communication data is stored in the proxy communication buffer 22 (step S48). Thereafter, the microcomputer 24 starts the timer T1 (step S49), and ends the reception process.

  If the received signal is a proxy communication completion notification (Y in step S34), the microcomputer 24 determines whether or not there is an ACK within a predetermined time (step S50). If there is an ACK within the predetermined time (Y in step S50), the microcomputer 24 determines whether or not the proxy communication data having the same data D as the received proxy communication completion notification is stored in the buffer 22 (step). S51).

  If proxy communication data having the same data D is stored (Y in step S51), the microcomputer 24 determines that communication is successful, clears the proxy communication buffer 22, and stops transmitting proxy communication data (step). S52). Thereafter, the microcomputer 24 stops the timer T1 that counts the first predetermined time Tw1 (step S53), and ends the reception process.

  On the other hand, when proxy communication data having the same data D is not stored (N in step S51), the microcomputer 24 sends a proxy communication completion notification having the same data D as the received proxy communication completion notification to the buffer 23. It is determined whether it is stored (step S54). If a proxy communication completion notification having the same data D is stored (Y in step S54), the microcomputer 24 clears the proxy communication completion notification buffer 23 and stops transmitting the proxy communication completion notification (step S55). The process proceeds to step S53. On the other hand, if the proxy communication completion notification having the same data D is not stored (N in step S54), the microcomputer 24 immediately ends the reception process.

  After receiving the proxy communication completion notification (Y in step S34), if the ACK cannot be received within a predetermined time or NCK is received (N in step S50), the microcomputer 24 proceeds to step S56. In step S56, the microcomputer 24 determines whether or not proxy communication data having the same data D as the received proxy communication completion notification is stored in the proxy communication buffer 22 (step S56).

  If proxy communication data having the same data D is stored (Y in step S56), the microcomputer 24 clears the proxy communication buffer 22 (step S57) and stops transmission of proxy communication data. Thereafter, the microcomputer 24 rewrites and stores the proxy communication completion notification source address As1 received in the proxy communication completion notification buffer 23 with its own node address (step S58), and then starts a timer T1 (step S59). The reception process ends.

  On the other hand, when the proxy communication data having the same data D is not stored (N in step S56), the microcomputer 24 determines whether or not the proxy communication completion notification having the same data D is stored in the proxy communication completion notification buffer 23. Is determined (step S60). When the proxy communication completion notification having the same data D is stored in the proxy communication completion notification buffer 23 (Y in step S60), the microcomputer 24 immediately ends the reception process. If not stored (N in step S60), the microcomputer 24 proceeds to step S58.

  Further, the microcomputer 24 performs a timer process for controlling the timers T1 and T2 in parallel with the transmission process and the reception process. The timer process of the microcomputer 24 will be described with reference to FIG. The timer T1 is started when the proxy communication data and the proxy communication completion notification are stored in the buffers 22 and 23 as described in the reception process described above. In the timer process, the microcomputer 24 monitors the timer T1, and determines whether or not the count value exceeds the first predetermined time Tw1 (step S70).

  If the first predetermined time Tw1 is exceeded (Y in step S70), the microcomputer 24 stops the timer T1 and starts the timer T2 (step S71). Thereafter, the microcomputer 24 sets a transmission prohibition flag in the proxy communication data and proxy communication completion notification stored in the buffers 22 and 23 (step S72).

  In the transmission process described above, even if the proxy communication data and the proxy communication completion notification are stored in the buffers 22 and 23, if the transmission prohibition flag is set, the microcomputer 24 regards these as not stored and transmits them. do not do. This prevents the proxy communication data and the proxy communication completion notification from being transmitted in the buffers 22 and 23 after the first predetermined time Tw1 has elapsed.

  When a signal having the same data D is received after the timer T2 is started, Y is determined in step S42 of the reception process. Accordingly, even after receiving the signal having the same data D as the proxy communication data that is no longer used or the proxy communication completion notification until the second predetermined time Tw2 elapses after the first predetermined time Tw1 has elapsed, ignore.

  After setting the transmission prohibition flag (step S72), the microcomputer 24 monitors the timer T2 and determines whether or not the count value exceeds the second predetermined time Tw2 (step S74). When the second predetermined time Tw2 is exceeded (Y in step S72), the microcomputer 24 clears the proxy communication buffer 22 and the proxy communication completion notification buffer 23 (step S74), and then proceeds to step S70.

  Next, transmission / reception of signals performed between the nodes A to D of the communication system 1 will be described with a specific example. The communication system 1 is configured as shown in FIG. That is, the node A is arranged so as to be able to perform wireless communication with the node B. The node B is arranged so as to be able to perform wireless communication with the nodes A and C. The node C is arranged so as to be able to wirelessly communicate with the node B and the node D. Node D is arranged to be able to communicate with node C wirelessly.

  First, the operation of the communication system 1 when a data transmission request to the nodes A to D is generated will be described with reference to FIG. When the node A issues a data communication request to the node D, the node A directly transmits the communication data.

  The direct communication data from the node A is received by the node B without reaching the node D. Since the node B cannot receive the ACK thereafter, the node B creates proxy communication data and stores it in the proxy communication buffer 22. As a result, the node A enters a state in which the communication data is directly stored and the node B stores the proxy communication data. The node A retransmits and the node B tries to perform the first transmission. The retransmission back-off time is set to the longest time as described in the first embodiment. Therefore, the node B obtains the transmission right, and the node B transmits the proxy communication data. The other nodes A, C and D hold the transmission.

  The proxy communication data transmitted from the node B does not reach the node D but is received by the node C. Since node C cannot thereafter receive ACK, node C creates proxy communication data and stores it in proxy communication buffer 22. As a result, the node A enters a state in which the communication data is directly stored, the node B stores the proxy communication data, and the node C stores the proxy communication data. The nodes A and B retransmit, and the node C attempts to perform the first transmission. Therefore, the node C obtains the transmission right, and the node C transmits the proxy communication data. The other nodes A, B and D hold the transmission.

  The proxy communication data transmitted from node C is received by node D, and node D transmits ACK to node C. At this time, node D is determined to have received data from node A. When receiving an ACK from the node D, the node C determines that the proxy communication is successful, discards the proxy communication data, and stores a proxy communication completion notification. As a result, the node A enters a state in which the direct communication data, the node B stores the proxy communication data, and the node C stores the proxy communication completion notification. The nodes A and B retransmit, and the node C attempts to perform the first transmission. Therefore, the node C obtains a transmission right, and the node C transmits a proxy communication completion notification.

  The proxy communication completion notification transmitted from the node C does not reach the node A but is received by the node B. Since the node B cannot receive the ACK thereafter, the node B discards the proxy communication data and stores the proxy communication completion notification. As a result, the node A enters a state in which the communication data is directly stored, the nodes B and C store the proxy communication completion notification, the nodes A and C retransmit, and the node B tries to perform the first transmission. Therefore, the node B obtains the transmission right, and the node B transmits a proxy communication completion notification.

  The proxy communication completion notification transmitted from node B reaches node A, and ACK is transmitted from node A to node B. At this time, the node A determines that the communication is completed, and cancels the subsequent retransmission processing. When receiving the ACK, the node B discards the proxy communication completion notification. When receiving the proxy communication completion notification from the node B, the node C discards the proxy communication completion notification.

  According to the second embodiment described above, proxy communication data and proxy communication completion notification can also be transmitted via a plurality of nodes.

Third Embodiment Hereinafter, a communication system 1 of the present invention in a third embodiment will be described with reference to FIG. The third embodiment is a modification of the second embodiment. In the communication system 1 illustrated in FIG. 15, the node A is arranged to be able to perform wireless communication with the node B. Node B is arranged so as to be able to wirelessly communicate with nodes C and D. The node C is arranged so as to be able to wirelessly communicate with the nodes B and D. The node D is arranged so as to be able to wirelessly communicate with the nodes B, C, and E. The node E is arranged so as to be able to wirelessly communicate with the node D.

  In the second embodiment, when the relay node stores the proxy communication data that is the same as the received proxy communication completion notification data D when it receives the proxy communication completion notification from another node, the proxy communication is completed. A notification was sent. That is, the route for returning the proxy communication completion notification to the transmission source node has not been determined. For this reason, in the communication system 1 shown in FIG. 15, the following problems may occur. In the communication system 1 shown in FIG. 15, the communication from the node A to the node E is relayed to the nodes E through the nodes B and D, and the proxy communication completion notification is also sent back to the node A through the nodes B and D. .

  However, since the node C can receive the proxy communication data from the node B and can receive the proxy communication completion notification from the node D, the proxy communication completion notification is also transmitted from the node C, and it is useless when there is no change in the communication status. Communication. Therefore, in the third embodiment, a list of nodes that have performed proxy communication up to the target node is added to the proxy communication data, and proxy communication completion notifications are transmitted in the reverse order of the list. When the communication situation changes and the proxy communication completion notification cannot be transmitted along the list, the proxy communication completion notification is transmitted as in the second embodiment.

  The frame configuration of the direct communication data, proxy communication data, and proxy communication completion notification of the third embodiment is as shown in FIG. In the third embodiment, a proxy communication list L is added. In the proxy communication list L, relay nodes that have performed proxy communication are stored in order so that their routes can be known.

  Next, the configuration of the communication node 20 (nodes A to E) will be described below with reference to FIG. In the figure, the same components as those shown in FIG. 10 already described in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. As shown in the figure, the microcomputer 24 further includes a list creation function 24O and a list confirmation function 24P in addition to the functions 24C to 24M described in the second embodiment.

  When the list creation function 24O receives direct communication data or proxy communication data that is not addressed to its own node (the destination address Ar1 is not its own node), the proxy communication stores the source address As1 in the buffer 22 in response to reception. It is added to the end of the data proxy communication list L. The list confirmation function 24P transmits a proxy communication completion notification according to the proxy communication list L of the proxy communication completion notification stored in the buffer 23.

  Next, the operation of the communication system 1 described above will be described. The microcomputer 24 executes transmission processing and reception processing in response to power-on. The transmission process in the third embodiment is equivalent to the transmission process shown in FIG. 4 described in the first embodiment. A significant difference from the first embodiment is the processing in step S14.

  In the first and second embodiments, the microcomputer 24 stores the transmission source address As2 of the proxy communication data transmitted in step S11 in the transmission destination address Ar1, but is different in the third embodiment. In the third embodiment, the microcomputer 24 checks the proxy communication list L of the proxy communication data transmitted in step S11, and stores the address of the node stored at the end in the destination address Ar1 (= relay destination node). To do. Others are the same as those in the first and second embodiments, and thus detailed description thereof is omitted here. The node stored at the end of the proxy communication list L is a node that has transmitted proxy communication data before its own node.

  The reception process of the microcomputer 24 described above will be described below with reference to FIG. When the microcomputer 24 receives from the antenna AT a signal whose ACK / NCK or source address As2 is other than the data of its own node, the microcomputer 24 starts reception processing. In the reception process, the microcomputer 24 determines whether or not the destination of the received signal (transmission destination address Ar1) is addressed to its own node (step S21).

  When the destination of the received signal is not addressed to its own node (Y in Step S21), the microcomputer 24 performs Steps S40 to S42, S28 to S34, and S43 to S60 as in the second embodiment. The difference from the second embodiment is that when the proxy communication data is stored in the proxy communication buffer 22, the address of the own node is added to the end of the proxy communication list L (steps S83 and S84). Since others are the same as that of 2nd Embodiment, detailed description is abbreviate | omitted here. Thereby, the proxy communication list L of the proxy communication data is stored so that the relay nodes of the proxy communication can be identified in order.

  On the other hand, if it is addressed to its own node (N in step S21), the microcomputer 24 determines whether or not the received signal is direct communication data or proxy communication data (step S22). If it is direct communication data or proxy communication data (Y in step S22), the microcomputer 24 performs steps S23 to S25 as in the first and second embodiments.

  If it is not direct communication data or proxy communication data (N in step S22), the microcomputer 24 determines whether it is a proxy communication completion notification (step S26). If it is a proxy communication completion notification (Y in step S26), the microcomputer 24 determines whether or not the transmission source address As2 is its own node (step S80). If the transmission source address As2 is its own node (Y in step S80), the microcomputer 24 determines that the communication of the proxy communication completion notification is successful, transmits ACK, and directly clears the communication buffer 21 (step S27). The reception process is terminated.

  On the other hand, if the transmission source address Ar2 is not the own node (N in step S80), the microcomputer 24 deletes the address of the own node stored at the end of the proxy communication list L of the received proxy communication completion notification. (Step S81). Thereafter, the microcomputer 24 stores the destination address Ar1 of the received proxy communication completion notification in the proxy communication completion notification buffer 23 with the destination address Ar1 as the last address of the proxy communication list L and the source address As1 as its own node address ( Step S82), the reception process is terminated. If it is not a proxy communication completion notification (N in step S26), the microcomputer 24 ends the reception process without doing anything.

  Next, the operation of the communication system 1 described above will be described below with reference to the sequence of FIG. First, the operation of the communication system when a data transmission request from the node A to the node B occurs will be described with reference to FIG. In the following description, the operations performed by the nodes A to D are actually executed by the microcomputers 24 of the nodes A to E.

  When the node A issues a data communication request to the node E, the node A directly transmits communication data. In this direct communication data, the source addresses As1 and As2 are the node A, the destination addresses Ar1 and Ar2 are the node D, the type S is the direct communication, and the proxy communication list L is blank.

  The direct communication data from the node A is received by the node B without reaching the node E. Since the node B cannot receive the ACK thereafter, the node B creates proxy communication data and stores it in the proxy communication buffer 22. In this proxy communication data, the source address As1 is node B, the source address As2 is node A, the destination addresses Ar1 and Ar2 are node E, the type S is proxy communication, and the proxy communication list L is node B. As a result, the node A enters a state in which the communication data is directly stored and the node B stores the proxy communication data. The node A retransmits and the node B tries to perform the first transmission. The retransmission back-off time is set to the longest time as described in the first embodiment. Therefore, the node B obtains the transmission right, and the node B transmits the proxy communication data. The other nodes A, C to E hold transmission.

  The proxy communication data transmitted from the node B does not reach the node E and is received by the nodes C and D. Since the nodes C and D cannot thereafter receive ACK, the proxy communication data is created and stored in the proxy communication buffer 22. At this time, the proxy communication data stored in the nodes C and D are respectively the source address As1 for the nodes C and D, the source address As2 for the node A, the destination addresses Ar1 and Ar2 for the node E, and the type S for proxy communication. Nodes C and D are added to the end of the proxy communication list L, respectively. As a result, the node A enters a state in which the communication data is directly stored, the nodes B to D store the proxy communication data, the nodes A and B are retransmitted, and the nodes C and D try to perform the first transmission.

  At this time, if the back-off time of node C is shorter than the back-off time of node D, node C obtains the transmission right, node C transmits proxy communication data, and nodes A, B, and D transmit Hold on. Of course, if the back-off time of the node D is shorter than the back-off time of the node C, the node D gets the transmission right. Here, an example in which the node C has the transmission right will be described.

  The proxy communication data from the node C does not reach the node E but is received by the node D. Since node D already has proxy communication data having the same data D, it does nothing. As a result, the nodes A to C retransmit, and the node D tries to perform the first transmission. Therefore, the node D obtains the transmission right and the node D transmits the proxy communication data. The other nodes A to C hold the transmission.

  The proxy communication data transmitted from node D is received by node E, and node E transmits ACK to node D. At this time, it is determined that node E has received data from node A. When receiving an ACK from the node E, the node D determines that the proxy communication is successful, discards the proxy communication data, and stores a proxy communication completion notification. In the proxy communication list L of the proxy communication completion notification, the proxy communication list L of the proxy communication data to be discarded is stored by deleting the address of the own node stored at the end thereof. Further, the node D is stored in the source address As1, the node A is stored in the source address Ar2, the node B is stored at the end of the proxy communication list L in the destination address Ar1, and the node E is stored in the destination address As2. The As a result, the nodes A to C retransmit, and the node D tries to perform the first transmission. Therefore, the node D obtains the transmission right, and the node D transmits a proxy communication completion notification.

  Node B and C receive the proxy communication completion notification transmitted from node D. When receiving the proxy communication completion notification in which the node B is stored in the transmission destination address Ar2, the node B transmits ACK. Further, the node B clears the proxy communication data from the proxy communication buffer 22, deletes the address of its own node stored in the terminal from the proxy communication list L of the received proxy communication completion notification, and sets the destination address As1. The data is rewritten to the node A stored in the terminal in the proxy communication list L after being deleted, and stored in the proxy communication completion notification buffer 23.

  At this time, the node C deletes the proxy communication data when receiving the ACK after receiving the proxy communication completion notification in which the own node is not stored in the transmission destination address Ar2, and thereafter, the proxy communication data also completes the proxy communication. Do not send notifications. When a failure occurs in communication between the node B and the node C and the ACK cannot be received from the node B, the proxy communication completion notification is transmitted from the node C.

  The proxy communication completion notification transmitted from the node B is received by the node A. When the node B proxy communication completion notification arrives at the node A, the node A transmits an ACK and clears the direct communication buffer 21 to stop the direct communication data retransmission. When the node B receives the ACK from the node A, the proxy communication buffer 22 and the proxy communication completion notification buffer 23 are cleared, and the retransmission of the proxy communication completion notification is stopped.

  According to the third embodiment described above, if the communication state does not change between when proxy communication data is transmitted and when proxy communication completion notification is returned, the proxy communication data is relayed to the relay destination node. The communication completion notification can be transmitted to the transmission source node, and the proxy communication completion notification is not transmitted from a node that is not the relay communication node of the proxy communication data. In addition, after sending proxy communication data, if any failure occurs on the route of proxy communication data, since reception notification cannot be received, proxy communication completion notification may be sent by relaying a node that is not a relay destination node. it can.

  In addition, according to embodiment mentioned above, the number of the communication nodes 20 and the arrangement position of the communication node 20 are not restricted to FIG. The number of communication nodes 20 may be two or more. The communication node 20 may be arranged at a position where it can communicate with at least one node.

  Also, the communication frames for direct communication data, proxy communication data, and proxy communication completion notification are not limited to those shown in FIGS. The order of each element is not limited. Further, other communication control information may be added.

  Further, according to the above-described embodiment, the data type is determined by the communication type S marker, but the present invention is not limited to this. Other markers and sequence numbers may be used.

  Further, according to the above-described embodiment, the target node is one of the plurality of nodes, but the present invention is not limited to this. Two target nodes may be used, or all nodes (unicast) constituting the communication system 1 may be used.

  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 20 communication node 24 microcomputer (direct communication means, reception notification means, first proxy communication means, second proxy communication means, first proxy communication completion notification means, second proxy communication completion notification means, communication collision avoidance means, Backoff time extension means, transmission stop means)
A to D nodes (communication nodes)

Claims (5)

In a communication system having a plurality of communication nodes capable of wireless communication and configuring a wireless mesh network,
Each of the plurality of communication nodes is
When a data transmission request occurs, direct communication means for transmitting direct communication data including the data, addressed to a target node, and having a node from which the data transmission request is generated as a transmission source;
A reception notification means for transmitting a reception notification;
If the direct communication data not addressed to the own node is received and then the reception notification cannot be received, the target node of the direct communication data including the data included in the direct communication data and the transmission source of the direct communication data First proxy communication means for transmitting proxy communication data addressed to
A first proxy communication completion notification means for transmitting a proxy communication completion notification addressed to a transmission source of the direct communication data upon receiving the reception notification after transmitting the proxy communication data;
A communication collision avoiding means for transmitting when a radio wave is not detected again after waiting for the back-off time to elapse after a state where the radio wave is not detected continues for a predetermined time;
After receiving the proxy communication data not addressed to its own node, when receiving the reception notification and the first proxy communication means trying to transmit the same proxy communication data as received, the back-off time is set. Means for extending the back-off time,
A transmission stop unit that stops transmission of the proxy communication data by the first proxy communication unit when receiving the proxy communication completion notification not addressed to the own node;
The reception notification means transmits the reception notification when receiving the direct communication data addressed to the own node and the proxy communication data. In a communication system having a plurality of communication nodes capable of wireless communication and configuring a wireless mesh network,
Each of the plurality of communication nodes is
When a data transmission request occurs, direct communication means for transmitting direct communication data including the data, addressed to a target node, and having a node from which the data transmission request is generated as a transmission source;
A reception notification means for transmitting a reception notification;
If the direct communication data not addressed to the own node is received and then the reception notification cannot be received, the target node of the direct communication data including the data included in the direct communication data and the transmission source of the direct communication data First proxy communication means for transmitting proxy communication data addressed to
A first proxy communication completion notification means for transmitting a proxy communication completion notification addressed to a transmission source of the direct communication data upon receiving the reception notification after transmitting the proxy communication data;
Receiving the proxy communication data is not addressed to the own node, then, if unable to receive the reception notification, and the second proxy communication unit configured to transmit the proxy communication data of which destination is the destination of the proxy communication data,
When the proxy communication completion notification that is not addressed to the own node is received, and then the reception notification cannot be received, the second proxy communication completion that transmits the proxy communication completion notification with the transmission destination of the proxy communication completion notification as the transmission destination And a notification means,
The reception notification means, when receiving the direct communication data addressed to the own node, the proxy communication data, and the proxy communication completion notification, transmits the reception notification. The first proxy communication means and the second proxy communication means transmit the proxy communication data obtained by adding the own node to a proxy communication list representing a relay node of the proxy communication data;
The first proxy communication completion notifying means obtains a node that has transmitted proxy communication data before its own node from the proxy communication list of the transmitted proxy communication data, and completes the proxy communication with the obtained node as a relay destination node. Send notifications,
When the second proxy communication completion notification means receives the proxy communication completion notification whose relay destination node is the local node, proxy communication data is sent before the local node from the proxy communication list of the received proxy communication completion notification. When the proxy communication completion notification is transmitted to the node that transmitted the proxy communication completion notification with the determined node as a relay destination node, and the relay destination node receives the proxy communication completion notification that is not its own node, the proxy from the relay destination node 3. The communication system according to claim 2, wherein when receiving the reception notification of the communication completion notification, transmission of the proxy communication completion notification is stopped. In a communication node constituting a wireless mesh network,
When a data transmission request occurs, direct communication means for transmitting direct communication data including the data, addressed to a target node, and having a node from which the data transmission request is generated as a transmission source;
A reception notification means for transmitting a reception notification;
If the direct communication data not addressed to the own node is received and then the reception notification cannot be received, the target node of the direct communication data including the data included in the direct communication data and the transmission source of the direct communication data First proxy communication means for transmitting proxy communication data addressed to
A first proxy communication completion notification means for transmitting a proxy communication completion notification addressed to a transmission source of the direct communication data upon receiving the reception notification after transmitting the proxy communication data;
A communication collision avoiding means for transmitting when a radio wave is not detected again after waiting for the back-off time to elapse after a state where the radio wave is not detected continues for a predetermined time;
After receiving the proxy communication data not addressed to its own node, when receiving the reception notification and the first proxy communication means trying to transmit the same proxy communication data as received, the back-off time is set. Means for extending the back-off time,
A transmission stop unit that stops transmission of the proxy communication data by the first proxy communication unit when receiving the proxy communication completion notification not addressed to the own node;
The reception node is configured to transmit the reception notification when receiving the direct communication data addressed to the own node and the proxy communication data. In a communication node constituting a wireless mesh network,
When a data transmission request occurs, direct communication means for transmitting direct communication data including the data, addressed to a target node, and having a node from which the data transmission request is generated as a transmission source;
A reception notification means for transmitting a reception notification;
If the direct communication data not addressed to the own node is received and then the reception notification cannot be received, the target node of the direct communication data including the data included in the direct communication data and the transmission source of the direct communication data First proxy communication means for transmitting proxy communication data addressed to
A first proxy communication completion notification means for transmitting a proxy communication completion notification addressed to a transmission source of the direct communication data upon receiving the reception notification after transmitting the proxy communication data;
Receiving the proxy communication data is not addressed to the own node, then, if unable to receive the reception notification, and the second proxy communication unit configured to transmit the proxy communication data of which destination is the destination of the proxy communication data,
When the proxy communication completion notification that is not addressed to the own node is received, and then the reception notification cannot be received, the second proxy communication completion that transmits the proxy communication completion notification with the transmission destination of the proxy communication completion notification as the transmission destination And a notification means,
The reception node is configured to transmit the reception notification when receiving the direct communication data addressed to the own node, the proxy communication data, and the proxy communication completion notification.

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