JP2020195071A - Wireless communication node and wireless communication system - Google Patents

Abstract

To provide a wireless communication node and a wireless communication system that can control transmission timing of the wireless communication node in which communication data is generated such that a plurality of pieces of communication data for which wireless communication has failed can be efficiently aggregated and proxy communication can be performed.SOLUTION: A wireless communication node that stores transmission order information includes a wireless receiving unit that receives communication data which is not addressed to the own node from another wireless communication node, a communication success/failure determination unit that determines the success/failure of communication of communication data not addressed to the own node received from the other wireless communication node and generates communication success/failure information, an override communication data storage unit that stores a plurality of pieces of communication data not addressed to the own node received from the other wireless communication node and communication success/failure information of the plurality of pieces of communication data in association with each other, and a communication timing management unit that calculates transmission timing on the basis of transmission node information and communication success/failure information of the plurality of pieces of communication data stored in the override communication data storage unit, and transmission order information.SELECTED DRAWING: Figure 5

Description

The present invention is a wireless communication node capable of controlling the transmission timing of a wireless communication node in which communication data is generated in order to efficiently aggregate a plurality of communication data for which wireless communication has failed and enable proxy communication. Regarding wireless communication systems.

In a mesh network including a plurality of wireless communication nodes, it is preferable to reduce the amount of communication by collecting a plurality of communication data held by the relay node (hereinafter, also referred to as a proxy communication node). Further, in the communication data generating node, it is preferable to control the communication timing so that the communication data can be easily collected in the relay node so that the effect of collecting the communication data can be obtained. In particular, in order to aggregate the communication data at the relay node, it is preferable that the communication data transmitting node reliably and quickly transmits the communication data.

For example, Patent Document 1 and Patent Document 2 disclose a configuration of a wireless communication node that periodically acquires necessary data from an interface and wirelessly transmits the data to the same destination as communication data. Since the communication data to be transmitted wirelessly also occurs at other nodes in the network, a configuration is disclosed in which the relay node collects these communication data in order to reduce the total traffic of the network. Then, in order to facilitate the collection of communication data in the relay node, a configuration is disclosed in which the transmission timing of the next node is changed based on the success or failure of the wireless communication of the immediately preceding transmission node.

The configuration of the prior art based on Patent Document 1 will be described with reference to FIGS. 6 and 7. The transmission order of the nodes is defined in advance, and when the communication of the node immediately before the transmission order fails, the node having the next transmission order performs wireless communication immediately after the communication failure.

In the example of FIG. 6, the number of aggregates (the number of aggregates) is 3, and node N'1 transmits communication data to node N'5. When it is confirmed that node N'2, node N'3, and node N'4 are overhearing (intercepting) this communication and node N'5 cannot receive the communication data of node N'1. Node N'4 queues the communication data from node N'1.

Since the node N'2 can detect that the communication of the node N'1 has failed, the node N'2 transmits the communication data owned by the node N'5 to the node N'5 immediately after the communication of the node N'1. Communication of node N'2 also overhears node N'3 and node N'4.

If the communication data of node N'2 does not reach node N'5 and communication fails, node N'4 queues the communication data of node N'2 and the node that has been queued first. When the communication data from N'1 is confirmed and it is confirmed that the destinations are the same, the two communication data are aggregated.

Since the communication of the node N'2 has failed, the node N'3 transmits the communication data owned by the node N'5 to the node N'5 immediately after the communication of the node N'2. The communication of node N'3 is overheard by node N'4.

If the communication data of node N'3 does not reach node N'5 and communication fails, node N'4 queues the communication data of node N'3 and queues node N first. When the communication data of '1 and node N'2 are confirmed and it is confirmed that they are the same destination, the three communication data are aggregated.

Since the three communication data are aggregated at the node N'4, the condition of the number of aggregates is satisfied, so proxy communication (Patent Document 3) is performed toward the node N'5. Patent Document 3 is a prior art document that describes proxy communication.

Japanese Patent Application No. 2018-010442 Japanese Patent Application No. 2018-131648 Japanese Unexamined Patent Publication No. 2014-225859

However, according to the configurations of Patent Documents 1 and 2, if a part of the data generation nodes succeeds in communication, there is a problem that the change of communication timing for aggregating the communication data may not work after the successful communication. is there.

Specifically, in FIG. 7, when the communication from the node N'1 to the node N'5 fails, the node N'2 whose communication timing is changed immediately after that transmits its own communication data to the node N'5. If the communication from node N'2 to node N'5 is successful, node N'3 does not change the communication timing, so node N'4 waits for a certain period of time and then performs proxy communication. May occur. In this case, since the node N'3 starts the communication after the communication of the node N'4, the communication data is not aggregated at the node N'4.
Therefore, an object of the present invention is to provide a means for solving such a problem.

In order to solve the above problems, the present invention adopts the following configuration.
That is, the invention of the wireless communication node according to claim 1 is
A wireless communication node that stores transmission order information in which the transmission order is predetermined and functions as a transmission node, a proxy communication node, and a reception node.
A wireless receiver that receives communication data that is not addressed to its own node from another wireless communication node,
A communication success / failure determination unit that determines the success / failure of communication of the communication data that is not addressed to the own node received from the other wireless communication node and generates communication success / failure information.
An override communication data storage unit that stores a plurality of the communication data not addressed to the own node received from the other wireless communication node and the communication success / failure information of the plurality of communication data in association with each other.
It is characterized by including a communication timing management unit that calculates transmission timing based on transmission node information and communication success / failure information of the plurality of communication data stored in the overhead communication data storage unit, and transmission order information. And.

According to the above configuration, even when a part of the data generation nodes succeeds in communication, the function of changing the communication timing for aggregating the communication data after the successful communication can operate properly.

In order to solve the above problem, in the invention according to claim 2, in the wireless communication node according to claim 1, the communication timing management unit can perform wireless communication of the wireless communication node which is the transmission order immediately before the own node. If it fails, the transmission timing is changed so that the communication data is transmitted immediately after the failed wireless communication, and if the failed wireless communication is not the wireless communication of the wireless communication node that is the immediately preceding transmission order, the relevant Changing the transmission timing of the wireless communication node so that the communication data is transmitted immediately after the wireless communication that failed, and changing the transmission timing of the own node so that the communication frames are adjacent from the changed transmission timing. It is characterized by.

According to the above configuration, if the previous node fails in communication, the next node sends communication data immediately after the failed communication, and if the node before the previous one fails in communication, it fails. Since the timing can be changed so that the communication frames immediately after the communication frames are adjacent to each other, the transmission timing can be changed so that the aggregation of communication data is efficient based on the communication history information.

In order to solve the above problem, the invention according to claim 3 is the wireless communication node according to claim 1 or 2, even when the communication timing management unit has communication data that cannot be overheard. It is characterized in that the transmission timing of the own node is calculated on the assumption that the communication data is transmitted with a predetermined communication frame length.

According to the above configuration, even if there is communication data that could not be overheard, the timing at which the own node should transmit the communication data from the past communication data and transmission order information stored in the overhear communication data storage unit is determined. It becomes possible to calculate appropriately.

In order to solve the above problems, the invention according to claim 4 is the wireless communication node according to any one of claims 1 to 3.
When there is no data to be transmitted to the local node, the proxy communication data storage unit that stores the communication data that is not addressed to the local node and the communication failed.
When there are a plurality of communication data stored in the proxy communication data storage unit, it is characterized by including a communication data synthesis unit that aggregates communication data having the same destination information and converts it into one communication data.

According to the above configuration, the wireless communication node can function as a proxy communication node when there is no data to be transmitted to the own node. In this way, the wireless communication node functions as a transmitting node when there is data to be transmitted to the own node, and functions as a proxy communication node when there is no data to be transmitted to the own node.

In order to solve the above problem, in the invention according to claim 5, in the wireless communication node according to claim 4, the communication timing management unit is stored in the proxy communication data storage unit when the aggregation condition is satisfied. The communication data is transmitted from the wireless transmission unit, and the aggregation condition is that the number of aggregated communication data that is not addressed to the own node is aggregated, or the communication data that is not addressed to the own node is aggregated. It is characterized by the aggregation time.

According to the above configuration, when the wireless communication node functions as a proxy communication node, the communication data in which communication failed before the aggregation condition is satisfied is efficiently aggregated, and then the proxy communication is performed as soon as the aggregation condition is satisfied. Becomes possible to execute.

In order to solve the above problems, the invention of the wireless communication system according to claim 6 is
A plurality of wireless communication nodes having the transmission function according to any one of claims 1 to 3.
At least one wireless communication node having the proxy communication function according to claim 5,
It is characterized by having.

According to the above configuration, even when a part of the data generation nodes succeeds in communication, the function of changing the communication timing for aggregating the communication data after the successful communication can operate properly.

In order to solve the above problem, the invention according to claim 7 is the wireless communication system according to claim 6, wherein the wireless communication system does not have a controller that centrally manages the operation timing of the wireless communication node. Each wireless communication node is characterized in that it transmits communication data based on the communication timing management unit of the own wireless communication node.

According to the above configuration, in a simple wireless communication system in which there is no controller that centrally manages the operation timing of the wireless communication node, a simple configuration is adopted by adopting a protocol such as CSMA / CA (Carrier Sense Multiple Access with Collision Availability). It is possible to build an efficient system.

In order to solve the above problems, the invention according to claim 8 is the wireless communication system according to claim 6 or 7, wherein the wireless communication system is mounted on a vehicle and the communication data is an electronic device provided on the vehicle. It is characterized in that it is the data output from.

According to the above configuration, in a vehicle, a large number of sensors, an ECU (Electronic Control Unit), etc. are arranged, a large amount of data is generated, and there is a concern that traffic in the network will increase. By using, it is possible to suppress the increase in traffic in the network and suppress the delay in communication.

According to the present invention, even when a part of the data generation nodes succeeds in communication, the function of changing the communication timing for aggregating the communication data after the successful communication can operate properly.

It is a schematic diagram which shows an example of the structure of the wireless network which constitutes a wireless communication system. It is a block diagram which shows an example of the main component of each node which constitutes a wireless network. It is a schematic diagram for demonstrating an example of the storage element of the override communication data storage part included in a node. It is a schematic diagram for demonstrating an example of the storage element of the proxy communication data storage part included in a node. It is a flowchart which shows the operation example of the node shown in FIG. It is a schematic diagram which shows an example of the structure of the wireless network which constitutes the wireless communication system which concerns on a prior art. 6 is a time chart showing an operation example of each node constituting the wireless network of FIG.

(Overview of wireless communication system)
In the present embodiment, the wireless communication system includes a plurality of wireless communication nodes, and each wireless communication node can function as a transmitting node, a relay node (hereinafter, may be referred to as a proxy communication node), and a receiving node. That is, each wireless communication node functions as a receiving node when the received communication data is addressed to its own node, and when it is not addressed to its own node and does not have communication data to be transmitted, each wireless communication node functions. Functions as a proxy communication node. Further, each wireless communication node functions as a transmitting node when the received communication data is not addressed to its own node and has communication data to be transmitted. The transmission order information is stored in each wireless communication node, and the transmission order of the own node can be determined.

When functioning as a transmitting node, it does not function to aggregate received communication data that is not addressed to its own node. That is, when functioning as a transmitting node, the received communication data that is not addressed to the own node is not stored in the proxy communication data storage unit 206 described later. However, the received communication data that is not addressed to the own node includes the transmission node information included in the communication data and the communication success / failure information indicating whether the communication of the communication data has succeeded or failed, as well as the overhear communication data described later. It is stored in the storage unit 209.

Therefore, when functioning as a transmission node, the transmission timing of the own node is calculated based on the transmission order information, the transmission node information, and the communication success / failure information. If the communication success / failure information includes communication failure information, the transmission timing of the local node is changed. When the communication success / failure information does not include the communication failure information, the transmission timing of the own node does not change because the communication frame for transmitting / receiving the communication data has a fixed length. If the communication of the immediately preceding communication data has failed, the communication data of the next node is transmitted immediately after it is determined to have failed. As a result, when the communication success / failure information includes the communication failure information, the subsequent transmission timing is changed according to the number of failures.

In the prior art, the transmission timing of the next transmitting node is changed immediately after the communication fails only when the communication of the immediately preceding transmitting node fails. Therefore, when the communication of the immediately preceding transmitting node succeeds, Subsequent transmission timings of the nodes may be before or after, or may be spaced apart. However, according to the above embodiment, since the transmission timings of the succeeding nodes are set adjacent to each other based on the plurality of transmission histories, the possibility that the transmission timings are appropriately set is increased, and the aggregation function is efficient. Increased chances of working hard.

When it functions as a proxy communication node, it functions to aggregate the received communication data. That is, when functioning as a proxy communication node, the received communication data is stored in the proxy communication data storage unit 206 described later, communication data having the same destination is aggregated, and when the aggregation condition is satisfied, the proxy communication is performed. To execute. The aggregation condition is either the number of aggregations or the aggregation time, and the number of aggregations and the aggregation time can be set to arbitrary values by the wireless communication system. In addition, the aggregation time may be a value that fluctuates during the operation of the wireless communication system.

The wireless communication system according to the present embodiment according to the above description can be mounted on a moving body such as a vehicle. In this case, the communication data transmitted by the transmitting node may be information such as sensor information for detecting the status of the moving body, information for controlling the moving body, and information for electronic devices mounted on the moving body. ..

The wireless communication system according to the present embodiment does not have a controller that controls the transmission / reception timing of each node, and employs a protocol such as CSMA / CA (Carrier Sense Multiple Access with Collection Avoidance).

(Operation example of wireless communication system)
An operation example of the wireless communication system will be described with reference to FIG.

In FIG. 1, a wireless communication system including a node N1, a node N2, a node N3, a node N4, and a node N5 is shown. In the following description of the operation example, the node N1, the node N2, and the node N3 are transmission nodes because they have communication data to be transmitted, and the node N4 is a relay node because they do not have communication data to be transmitted. .. Further, the node N1, the node N2, and the node N3 are trying to transmit the communication data to the node N5 as a destination. Further, the transmission order is predetermined as the transmission order information, and the node N1, the node N2, the node N3, the node N4, and the node N5 store the transmission order information. The transmission order information in this embodiment is in the order of node N1 → node N2 → node N3 → node N4 → node N5.

First, in FIG. 1, node N1 transmits communication data to node N5 as a destination. The communication data transmitted by the node N1 is overheard by the node N2, the node N3, and the node N4.

When the node N2, the node N3, and the node N4 confirm that the node N5 has not normally received the communication data from the node N1, the node N4 queues the communication data. That is, the node N4 stores the communication data from the node N1 and the destination information of the communication data in the proxy communication data storage unit 206. The destination information in this case is the identification information of the node N5. Note that the node N1 may set a retransmission flag for resending communication data for which communication has failed.

Since the node N3 is the node to be communicated next to the node N2, it is said that the communication data of the node N1, the transmission node information of the communication data, and the communication of the communication data have failed in the override communication data storage unit 209. The communication success / failure information is stored so as to indicate the information. The communication data of the node N1 is stored in the part (N-2) of FIG. 3 (N is the communication order of the own node). Next, the node N3 calculates the transmission timing of its own node. In this case, since the communication of the node N2 should come after the communication of the node N1, one communication frame is provided for the node N2 immediately after the communication of the node N1 fails, and the communication timing of the node N3 is communicated. The timing management unit 208 determines. Note that one communication frame has a fixed length, and the wireless communication system can set the fixed length to an arbitrary length.

Since the node N2 is the node to communicate with after the node N1, the communication data held by the node N2 is transmitted to the node N5 immediately after the communication failure of the node N1.

Node N3 and node N4 also overhear the communication data of node N2.

When the communication data of the node N2 is normally received by the node N5 and the acknowledgment (ACK (ACKnowedgement)) from the node N5 is overheard by the node N3 and the node N4, the node N4 receives the communication data of the node N2. Discard.

Since the node N3 is the node to be communicated next to the node N2, it is said that the communication data of the node N2, the transmission node information of the communication data, and the communication of the communication data are successfully communicated to the overhead communication data storage unit 209. Stores communication success / failure information indicating information. The communication data of the node N2 is stored in the part (N-1) of FIG. 3 (N is the communication order of the own node). Next, the node N3 calculates the transmission timing of its own node. The transmission timing of the communication data of the node N3 is set immediately after the communication of the node N2.

Node N4 also overhears the communication data of node N3.

When the node N4 confirms that the node N5 has not normally received the communication data from the node N3, the node N4 queues the communication data. That is, the node N4 stores the communication data from the node N3 and the destination information of the communication data in the proxy communication data storage unit 206. The destination information in this case is the identification information of the node N5. When the node N4 confirms the communication data of the previously queued node N1 and confirms that they are the same destination (node N5 in this case), the communication data of the node N1 and the communication data of the node N3 are aggregated. , Make one communication data as one packet.

At node N4, the number of aggregated communication data is 2, but if the aggregation waiting time, which is a predetermined time, has elapsed since the communication data of node N1 was queued, it is aggregated with node N5 as the destination. The packet is immediately transmitted to the node N5.

(Configuration example of wireless communication node)
The main functions of the wireless communication node 200 (hereinafter, may be simply referred to as a node) for realizing the above-mentioned functions will be described with reference to the block diagram of FIG.

The nodes are an antenna ANT, a wireless reception unit 202, a wireless transmission unit 203, a destination determination unit 204, a communication success / failure determination unit 205, a proxy communication data storage unit 206, a communication data synthesis unit 207, a communication timing management unit 208, and an override communication data. It is composed of a storage unit 209 and an I / F unit 210 and 211. The node may be configured to include a transmission / reception switching unit 201.

The wireless receiving unit 202 has a function of receiving communication data transmitted from another node. The communication data may be communication data addressed to the local node or may not be communication data addressed to the local node. Receiving communication data that is not addressed to the local node is called overhearing (interception).

The wireless transmission unit 203 has a function of transmitting communication data from the node. The communication data may be data generated in the own node, or may be communication data in which communication that is not addressed to the own node that has been overheard has failed and is communication data for proxy communication.

The destination determination unit 204 has a function of referring to the destination information of the communication data received by the wireless reception unit 202 to distinguish the communication data addressed to the own node from the communication data addressed to another node. As an example, the destination information is node identification information, which can be referred to as information included in the header.

The communication success / failure determination unit 205 has a function of determining whether or not the communication of the communication data addressed to the other node is successful when the communication data addressed to the other node is overheard. For example, when an acknowledgment (ACK) for communication data addressed to another node can be overheard, the communication success / failure determination unit 205 can determine that the communication of the communication data is successful. Further, for example, when a negative response (NACK (Negative ACKnowledgement)) to communication data addressed to another node can be overheard, or when an acknowledgment (ACK) and a negative response (NACK) cannot be overheard, communication is performed. The success / failure determination unit 205 can determine that the communication of the communication data has failed. The success or failure of communication is stored as communication success / failure information in the overwrite communication data storage unit 209, which will be described later.

The proxy communication data storage unit 206 has a function of temporarily storing communication data destined for another overheared node and communication data for which communication has failed. In addition, destination information indicating the destination node of the communication data included in the communication data is also stored. For example, when the communication of the node of the communication order (N-2) fails, the communication data of the communication order (N-2) and the communication data of the communication order (N-2) should be transmitted. Destination information as identification information (for example, node X) is stored (see FIG. 4, N is the communication order of the own node). Further, in FIG. 4, when the communication of the node of the communication order (Nn) fails, the communication data of the communication order (Nn) and the communication data of the communication order (Nn) are transmitted. It is also shown that the destination information as the identification information (for example, node X) of the power node is stored (n is the number of aggregates).

The communication data synthesis unit 207 synthesizes a plurality of communication data having the same destination (aggregate) when there are a plurality of communication data in the proxy communication data storage unit 206 in which communication that is not addressed to the own node has failed due to overhearing of wireless communication. ) And has the function of integrating into one packet. That is, it is possible to reduce the total number of packets transmitted by synthesis.

The communication timing management unit 208 has a function of determining the communication timing in which the own node communicates from the communication data stored in the override communication data storage unit 209. Each node transmits communication data in order in a fixed-length communication frame, but if the communication of the immediately preceding node fails, the next node transmits communication data immediately after that. Since the history of communication success / failure information indicating that communication has failed or succeeded is stored in the override communication data storage unit 209, each node can adjust the communication timing of its own node based on the communication success / failure information. become.

More specifically, the communication timing management unit 208 determines the transmission timing based on the transmission node information and the communication success / failure information of the plurality of communication data stored in the override communication data storage unit 209, and the transmission order information. Calculate. The transmitting node information is information included in the communication data. The transmission order information is the information stored in each node, and the node identification information is the information stored corresponding to the transmission order.

Specifically, the communication timing management unit 208 sets the transmission timing so that when the wireless communication of the wireless communication node, which is the transmission order immediately before the own node, fails, the communication data is transmitted immediately after the failed wireless communication. If the wireless communication that has been changed and failed is not the wireless communication of the wireless communication node that is the previous transmission order, the transmission timing of the wireless communication node is set so that the communication data is transmitted immediately after the failed wireless communication. Is changed, and the transmission timing of the own node is changed so that the communication frames are adjacent to each other from the changed transmission timing.

The over-hear communication data storage unit 209 is communication data that is not addressed to the own node and is not addressed to the own node and is acquired from another node due to over-hear of wireless communication, and communication data indicating communication failure, communication indicating success or failure of communication of the communication data. It has a function of associating and storing success / failure information and transmission node information indicating a transmission node of the communication data. The details of the overwrite communication data storage unit 209 are shown in FIG.

The I / F (interface: Interface) unit 210 has a function of outputting received communication data addressed to the own node to an electronic device such as an in-vehicle electronic device (ECU (Electronic Control Unit) or the like) connected to the own node. Have. The electronic device is not limited to the electronic device mounted on the vehicle.

The I / F (interface: Interface) unit 211 inputs data information output from an electronic device such as an in-vehicle device (for example, a switch or a sensor) connected to its own node, generates communication data, and is a communication timing management unit. It has a function to output to 208. As an example, the sensor may be a sensor that detects the traveling speed of the vehicle or a sensor that detects the rotational speed of the engine. However, as described above, the electronic device is not limited to the electronic device mounted on the vehicle.

The transmission / reception switching unit 201 as an option has a function of switching the connection between the antenna ANT and the wireless receiving unit 202 and the connection between the antenna ANT and the wireless transmitting unit 203. That is, the transmission / reception switching unit 201 has a function of connecting the antenna ANT and the wireless reception unit 202 when receiving communication data, and connecting the antenna ANT and the wireless transmission unit 203 when transmitting communication data.

However, in the case of a node that does not have the transmission / reception switching unit 201 as an option, the antenna ANT1 (not shown) is fixedly connected to the wireless receiving unit 202, and the antenna ANT2 (not shown) is connected to the wireless transmitting unit 203. It can also be configured to be fixedly connected. Further, the antennas ANT, ANT1 and ANT2 can be arranged inside or outside the node.

(Flowchart of operation example of wireless communication node)
A flowchart of an operation example of the wireless communication node 200 having the above configuration will be described with reference to FIG.

In step S501, the wireless receiving unit 203 of the node confirms whether or not communication data has been received. If the communication data is received (step S501: YES), the node proceeds to step S502, and if the communication data is not received (step S501: NO), the node proceeds to step S517.

In step S502, the destination determination unit 204 of the node confirms whether or not the received communication data is the communication data addressed to the own node. When the received communication data is the communication data addressed to the own node (step S502: YES), the node proceeds to step S503, and when the received communication data is not the data addressed to the own node (step S502: NO). The node proceeds to step S504. If the node proceeds to step S503, the node functions as a receiving node.

In step S503, since the received communication data is the communication data addressed to the own node, the node transmits an acknowledgment ACK indicating that the reception was successful to the other node that has transmitted the communication data, and ends the process. However, if the communication data cannot be received normally, a negative response NACK is transmitted to end the process.

In step S504, since the received (overheared) communication data is not addressed to the own node, the node confirms whether or not there is communication data to be transmitted to the own node. If there is communication data to be transmitted to the local node (step S504: YES), the node proceeds to step S505, and if there is no communication data to be transmitted to the local node (step S504: NO), the node steps. Proceed to S512.

If the node proceeds to step S505, the node functions as a transmitting node. When functioning as a transmitting node, the communication data aggregation function does not work. If the node proceeds to step S512, the node functions as a proxy communication node. When functioning as a proxy communication node, the communication data aggregation function works.

In step S505, the node stores the overhear communication data in the overhear communication data storage unit 209. The node then proceeds to step S506.

In step S506, the node overhears and confirms whether or not the communication of the overheared communication data is successful. If the communication of the overheard communication data is successful, the node can override the ACK of the communication data, and if the communication of the overheard communication data fails, the node can ACK the communication data. Can't overhear. If the communication of the overheard communication data is successful (step S506: YES), the node proceeds to step S507, and if the communication of the overheard communication data fails (step S506: NO), the node steps. Proceed to S508.

In step S507, the node stores the information indicating that the communication of the overheared communication data is successful in the overhear communication data storage unit 209, and ends the process. Information indicating that the overheard communication data has been successfully communicated can be stored as an example in a 1-bit pattern. Specifically, as an example, the information indicating that the communication was successful is indicated by "1" or "0", and the information indicating that the communication has failed is indicated by "0" or "1". It is associated with the communication data and stored in the overwrite communication data storage unit 209. That is, as an example, the communication success / failure information can be represented by one bit.

In step S508, the node stores the information indicating that the communication of the overheared communication data has failed in the overhear communication data storage unit 209, and proceeds to step S509. As described above, the information indicating that the communication of the overheard communication data has failed can be stored as an example in a 1-bit pattern.

In step S509, the node confirms whether or not the overheared communication data is the communication data transmitted by the node immediately before, that is, immediately before the own node. The order of transmission by each node is stored by each node as transmission order information. If the overheared communication data is the communication data transmitted by the immediately preceding node (step S509: YES), the node proceeds to step S510. If the overheared communication data is not the communication data transmitted by the immediately preceding node (step S509: NO), the node proceeds to step S511.

In step S510, since it is the order in which the own node transmits, the corresponding node transmits the data to be transmitted as communication data from the wireless communication unit 204 via the transmission / reception switching unit 202 and the antenna 201, and ends the process. To do. In this way, when the overheared communication data is the communication data transmitted by the immediately preceding node and the communication has failed, the communication is performed immediately after the communication in which the node in the next transmission order fails. Can be started.

In step S511, since the overheared communication data is not the communication data transmitted by the node immediately before the own node, that is, the node immediately before the node, refer to the history of the communication data stored in the overhear communication data storage unit 209. Then, the transmission timing is calculated. Since the method of calculating the transmission timing has been described above, the description thereof will be omitted here.

In step S512, since the node functions as a proxy communication node, the node stores the overheared communication data in the proxy communication data storage unit 206. That is, when the overheared communication data is not the communication data addressed to the own node and there is no communication data to be transmitted to the own node, the overheared communication data is stored in the proxy communication data storage unit 206. Next, the node proceeds to step S519.

In step S519, the node overhears and confirms whether or not the communication of the overheared communication data is successful. If the communication of the overheard communication data is successful, the node can override the ACK of the communication data, and if the communication of the overheard communication data fails, the node can ACK the communication data. Can't overhear. If the communication of the overheard communication data is successful (step S519: YES), the node proceeds to step S520, and if the communication of the overheard communication data fails (step S519: NO), the node steps. Proceed to S513.

In step S519, since the node has succeeded in communicating the overheared communication data, the node discards the communication data stored in the proxy communication data storage unit 206. That is, the node deletes the communication data from the proxy communication data storage unit 206. This is because the communication data for which communication is successful does not need to perform proxy communication. The node then proceeds to step S513.

In step S513, the node updates the aggregation wait timer. For example, the aggregation wait timer is counted up when the overheared communication data is not the communication data addressed to the local node and there is no communication data to be transmitted to the local node. In this case, the aggregation wait timer functions as a counter. That is, when the node functions as a proxy communication node, the aggregation wait timer is counted up every time communication data is received. Next, the node proceeds to step S514.

In step S514, the communication data synthesis unit 207 of the node aggregates the communication data having the same destination among the communication data stored in the proxy communication data storage unit 206 into one communication data. The node then proceeds to step S515.

In step S515, the node confirms whether or not the aggregation condition for proxy communication of the aggregated communication data is satisfied. The aggregation condition is a condition defined by the number of aggregation and the aggregation waiting timer, and the node confirms whether or not any of the conditions is satisfied. If the aggregation condition is satisfied (step S515: YES), the node proceeds to step S516, and if the aggregation condition is not satisfied (step S515: NO), the node ends the process. The number of aggregates is a number indicating how many communication data stored in the proxy communication data storage unit 206 are aggregated.

In step S516, the node proxy-communicates the communication data stored in the proxy communication data storage unit 206, or transmits the communication data generated in the own node, and the process ends.

In step S517, the node communication timing management unit 208 determines whether or not the transmission timing of the own node has arrived. If it is the transmission timing of the own node (step S517: YES), the node proceeds to step S516, and if it is not the transmission timing of the own node (step S517: NO), the node proceeds to step S521.

In step S521, the node confirms whether or not there is communication data to be transmitted to the own node. That is, a node having communication data to be transmitted functions as a transmitting node, and a node having no communication data to be transmitted functions as a proxy communication node. When there is communication data to be transmitted to the local node (step S521: YES), the node ends the process as a communication node, and when there is no communication data to be transmitted to the local node (step S521: NO). , The node proceeds to step S518 as a proxy communication node.

In step S518, the node updates the aggregation wait timer.

(Modification example 1 of node operation)
In the above description of the embodiment, the case where the node N1 fails in communication and the node N2 succeeds in communication has been described, but the same operation occurs when the node N1 succeeds in communication and the node N2 fails in communication. Become.

Specifically, in the node N3, the communication data of the node N1 is stored in the override communication data storage unit 209. Since the communication of the node N1 is successful, the node N3 does not calculate to change the communication timing. Next, communication of node N2 occurs, node N3 overhears the communication data of node N2, and stores the communication data in the overhear communication data storage unit 209. Since the communication of the node N2 is the communication immediately before the node N3, the node N3 changes the communication timing and transmits the communication data owned by the node N5 to the node N5 immediately after the communication failure of the node N2. However, as described above, the communication of the node N3 fails.

Node N4 overhears and queues the communication data of node N2 and node N3 in which communication has failed. That is, the node N4 stores the communication data of the node N2 and the node N3 in the proxy communication storage unit 206, aggregates the communication data, and transmits the aggregated communication data to the node N5.

(Modification example 2 of node operation)
As another example, when the communication is successful for both the node N1 and the node N2, the node N3 stores these communication data in the overhead communication data storage unit 209, but since both communication is successful, the node N3 stores the communication data. Do not change the communication timing.

Further, when the node N3 cannot overhear the communication of the node N2, if it can be confirmed that the communication of the node N1 has failed, the communication data owned by the node N1 can be transmitted at the timing calculated from the failure. It will be possible.

Although the embodiments have been described in detail with reference to the drawings, the present invention is not limited to the contents described in the above embodiments. In addition, the components described above include those that can be easily assumed by those skilled in the art and those that are substantially the same. Further, the configurations described above can be combined as appropriate. In addition, various omissions, substitutions or changes of the configuration can be made without departing from the gist of the present invention.

The present invention is a wireless communication node capable of controlling the transmission timing of a wireless communication node in which communication data is generated in order to efficiently aggregate a plurality of communication data for which wireless communication has failed and enable proxy communication. It is extremely useful for use in wireless communication systems.

ANT ・ ・ ・ Antenna 200 ・ ・ ・ Wireless communication node 201 ・ ・ ・ Transmission / reception switching unit 202 ・ ・ ・ Wireless reception unit 203 ・ ・ ・ Wireless transmission unit 204 ・ ・ ・ Destination judgment unit 205 ・ ・ ・ Communication success / failure judgment unit 206 ・・ ・ Proxy communication data storage unit 207 ・ ・ ・ Data synthesis unit 208 ・ ・ ・ Communication timing management unit 209 ・ ・ ・ Overhire communication data storage unit 210, 211 ・ ・ ・ I / F unit

Claims (8)

A wireless communication node that stores transmission order information in which the transmission order is predetermined and functions as a transmission node, a proxy communication node, and a reception node.
A wireless receiver that receives communication data that is not addressed to its own node from another wireless communication node,
A communication success / failure determination unit that determines the success / failure of communication of the communication data that is not addressed to the own node received from the other wireless communication node and generates communication success / failure information.
An override communication data storage unit that stores a plurality of the communication data not addressed to the own node received from the other wireless communication node and the communication success / failure information of the plurality of communication data in association with each other.
It is characterized by including a communication timing management unit that calculates transmission timing based on transmission node information and communication success / failure information of the plurality of communication data stored in the overhead communication data storage unit, and transmission order information. Wireless communication node. When the wireless communication of the wireless communication node, which is the transmission order immediately before the own node, fails, the communication timing management unit changes the transmission timing so as to transmit the communication data immediately after the failed wireless communication, and fails. If the wireless communication performed is not the wireless communication of the wireless communication node that is the immediately preceding transmission order, the transmission timing of the wireless communication node is changed so that the communication data is transmitted immediately after the failed wireless communication. The wireless communication node according to claim 1, wherein the transmission timing of the own node is changed so that the communication frames are adjacent to each other from the changed transmission timing. The communication timing management unit is characterized in that even if there is communication data that could not be overheard, the transmission timing of the own node is calculated assuming that the communication data is transmitted with a predetermined communication frame length. The wireless communication node according to claim 1 or 2. When there is no data to be transmitted to the local node, the proxy communication data storage unit that stores the communication data that is not addressed to the local node and the communication failed.
The first aspect of the present invention is that when there are a plurality of communication data stored in the proxy communication data storage unit, the communication data synthesis unit that aggregates the communication data having the same destination information into one communication data is provided. The wireless communication node according to any one of 3 to 3. When the aggregation condition is satisfied, the communication timing management unit causes the wireless transmission unit to transmit the communication data stored in the proxy communication data storage unit.
The claim is characterized in that the aggregation condition is the aggregation number of communication data for which communication not addressed to the own node has failed, or the aggregation time for aggregation of communication data for which communication not addressed to the own node has failed. Item 4. The wireless communication node according to item 4. A plurality of wireless communication nodes having the transmission function according to any one of claims 1 to 3.
At least one wireless communication node having the proxy communication function according to claim 5,
A wireless communication system characterized by comprising. The wireless communication system does not have a controller that centrally manages the operation timing of the wireless communication nodes, and each wireless communication node transmits communication data based on the communication timing management unit of the own wireless communication node. The wireless communication system according to claim 6. The wireless communication system according to claim 6 or 7, wherein the wireless communication system is mounted on a vehicle, and the communication data is data output from an electronic device provided in the vehicle.

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