JP2013207600A - Communication node, communication system, and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve security of communication.SOLUTION: A first communication node includes a first error detection code operation unit for calculating a first error detection code, based on data to be transmitted to a second communication node and a counter value representing transmission order of the data, using the counter value as a seed, and a transmission control unit for controlling transmission of a data frame, which includes the first error detection code and the data, to the second communication node. The second communication node includes a communication module for receiving a data frame from the first communication node, a second error detection code operation unit for calculating a second error detection code based on data in the data frame and a counter value representing receiving order of the data, using the counter value as a seed, an error detection unit for determining whether the second error detection code matches a first error detection code in the data frame or not, and a signal processing unit for performing a process according to the data in the data frame, based on the determination result of the error detection unit.

Description

  The present invention relates to a communication system mounted on a vehicle, for example.

  In many cases, an in-vehicle network is constructed in a vehicle in order to perform various controls in the vehicle. The in-vehicle network is realized by connecting many electronic control units (ECUs), sensors, actuators, and the like to the LAN. Hereinafter, electronic control units, sensors, actuators, and the like connected to the in-vehicle network are referred to as communication nodes. Communication nodes are installed at various positions in the vehicle. Communication nodes are connected by communication lines or electric wires.

  As a method for the communication node to confirm whether or not the received data is correct, there is a method proposed in the E2E protocol that is being studied by AUTOSAR (Automatic Open System Architecture). In the method proposed in the E2E protocol, the transmitting side transmits the CRC and the counter value simultaneously with the data. The receiving side confirms the certainty of the data based on the CRC and the counter value.

  A communication device that can suppress malfunction of an external device even if the communication bus is short-circuited by determining a short-circuit failure of the communication bus based on the CRC value is known (for example, see Patent Document 1).

JP 2010-130091 A

  As described above, there is a method proposed in the E2E protocol as a method for confirming whether received data is correct.

  A case where the method proposed in the E2E protocol is applied to a CAN (Controller Area Network) will be described.

  In CAN, four types of frames representing different types of information called “data frame”, “remote frame”, “error frame”, and “overload frame” are defined. In CAN, the size of the data area is defined as 8 bytes or less.

  FIG. 1 shows an example of a data frame when a method proposed in the E2E protocol is applied to CAN. The data frame includes a data field, arbitration, control, error detection code, and ACK field. In FIG. 1, the arbitration, control, and ACK fields are omitted.

  FIG. 1 shows an example in which the sum of the data field and the error detection code is 8 bytes. When the sum of the CRC and the counter value size is 2 bytes, 2 bytes are occupied by the CRC and the counter value in the 8-byte data field. That is, of the 8 bytes, 2 bytes are occupied in order to confirm the certainty of the data. The ratio of data for confirming the accuracy of data is large with respect to data to be transmitted, and the communication load is large.

  Since the communication load is large, to apply the method proposed in the E2E protocol to CAN, it may be necessary to increase the bus load of the entire network. In addition, you may have to consider adding more data lines. You may also have to review the data layout.

  The present invention has been made in view of the above points, and an object thereof is to improve the safety of communication.

The communication node of one embodiment of the disclosure is
A communication node included in the communication system,
A first error detection code computing unit that calculates a first error detection code using the counter value as a seed based on data to be transmitted to another communication node and a counter value representing the transmission order of the data;
A transmission control unit configured to control transmission of a data frame including the first error detection code calculated by the first error detection code calculation unit and the data to the other communication node;

The communication node of one embodiment of the disclosure is
A communication node included in the communication system,
A communication module for receiving data frames from other communication nodes;
An error detection code calculation unit that calculates an error detection code using the counter value as a seed based on data included in the data frame received by the communication module and a counter value indicating the reception order of the data;
An error detection unit that determines whether or not the error detection code calculated by the error detection code calculation unit and the error detection code included in the data frame match;
A signal processing unit that performs processing according to data included in the data frame based on a determination result by the error detection unit.

A communication system according to an embodiment of the disclosure includes:
A communication system having a plurality of communication nodes,
The first communication node is
A first error detection code computing unit that calculates a first error detection code using the counter value as a seed based on data to be transmitted to the second communication node and a counter value representing the transmission order of the data; ,
A transmission control unit that performs control to transmit a data frame including the first error detection code calculated by the first error detection code calculation unit and the data to the second communication node;
The second communication node is
A communication module for receiving a data frame from the first communication node;
Second error detection for calculating a second error detection code using the counter value as a seed based on data included in the data frame received by the communication module and a counter value indicating the reception order of the data A sign calculation unit;
An error detection unit that determines whether or not the second error detection code calculated by the second error detection code calculation unit matches the first error detection code included in the data frame;
A signal processing unit that performs processing according to data included in the data frame based on a determination result by the error detection unit.

A communication method according to an embodiment of the disclosure is as follows.
A communication method in a communication system having a plurality of communication nodes,
The first communication node is
Based on the data to be transmitted to the second communication node and the counter value representing the transmission order of the data, the first error detection code is calculated using the counter value as a seed,
Performing control to transmit a data frame including the first error detection code and the data to the second communication node;
The second communication node is
Receiving a data frame from the first communication node;
Based on the data included in the data frame and the counter value representing the reception order of the data, the second error detection code is calculated using the counter value as a seed,
Determining whether the second error detection code and the first error detection code included in the data frame match;
Based on the determination result, processing according to the data included in the data frame is performed.

  According to the disclosed embodiments, communication security can be improved.

It is a figure which shows an example of a data frame. It is a figure which shows one Example of a communication system. It is a figure which shows one Example of a communication system. It is a figure which shows one Example of a data frame. It is a figure which shows one Example of a communication node. It is a functional block diagram which shows one Example of a communication node. It is a flowchart which shows one Example of operation | movement of a communication node. It is a flowchart which shows one Example of operation | movement of a communication node.

Next, the form for implementing this invention is demonstrated, referring drawings based on the following Examples.
In all the drawings for explaining the embodiments, the same reference numerals are used for those having the same function, and repeated explanation is omitted.

<Example>
<Communication system>
FIG. 2 shows an embodiment of a communication system.

The communication system includes a plurality of communication nodes 100 _n (n is an integer of n> 0). FIG. 2 shows an example where n = 4. The value of n can be changed as appropriate according to the number of communication nodes included in the communication system. Further, the communication system may include one or a plurality of other communication nodes (not shown) connected to each communication node 100 _n . When a plurality of other communication nodes are included, the other communication nodes are preferably connected to a communication node arranged at the closest position among the plurality of communication nodes 100 _n .

The communication node 100 _n may be realized by an electronic control unit (ECU) or the like. The other communication node may be realized by an electronic control unit, or may be realized by a sensor, an actuator, or the like.

Specifically, an in-vehicle network is configured by connecting a plurality of communication nodes 100 _n to the data bus 150. The in-vehicle network includes a CAN (Controller Area Network). For CAN, hardware specifications and software specifications are defined by ISO15118. The in-vehicle network may include a LIN (Local Interconnect Network). Further, the in-vehicle network may include one that performs communication according to FlexRay (registered trademark).

The communication node 100 _n is connected to the data bus 150. The communication node 100 _n is mounted on a moving body such as a vehicle. In one embodiment of the communication system, it is mounted on a vehicle.

  FIG. 3 shows an embodiment of a communication system mounted on a vehicle. FIG. 3 shows an example in which the communication system shown in FIG. 2 is mounted on a vehicle.

In one embodiment of the communication system, the communication node 100 _n is mounted on an engine, a drive system, a transmission, a body, and the like. Engine, drive train, transmission, regardless of the body, the mounting position of the communication node 100 _n may be changed as appropriate.

In the example shown in FIG. 3, the communication node 100 ₁ can be a brake electronic control unit for controlling the brake. The communication node 100 ₂ may be an electronic engine control unit for controlling the engine. The communication node 100 ₃ may be a meter electronic control unit for controlling the meter. The communication node 100 ₄ may be a door electronic control unit for controlling the opening and closing of the door. An electronic control unit having a function of controlling a brake, an electronic control unit having a function of controlling an engine, an electronic control unit having a function of controlling a meter, and a control unit other than an electronic control unit having a function of controlling opening / closing of a door May be included.

  In one embodiment of the communication system, when calculating an error detection code, a seed and data to be transmitted (hereinafter referred to as “data”) are used. Specifically, the counter value of the counter is used as a seed. The counter value of the counter may represent the data transmission order. When the data transmission order is indicated, the counter value changes with the data transmission. For example, the counter value of the counter changes with data transmission. In one embodiment of the communication system, a case where the counter value increases by 1 as data is transmitted will be described. Specifically, every time one frame is transmitted, the counter value increases by one. The change in the counter value can be set as appropriate.

  As the error detection code, a cyclic code (CRC: Cyclic Redundancy Check) may be used, a checksum may be used, or a hash function may be used. The error detection code is not limited to a cyclic code, a checksum, and a hash function as long as the code error can be detected when a code error (error) occurs in the data. By using an error detection code or the like, the reliability of the communication system can be ensured. When a code error (error) occurs in data, a data that can detect and correct the code error may be used.

  In one embodiment of the communication system, a case where a cyclic code is used as an error detection code will be described.

  A communication node that transmits data (hereinafter referred to as “transmission node”) calculates an error detection code using the counter value and the data. That is, the error detection code is calculated from the counter value indicating the data transmission order and the data. The transmitting node transmits a data frame including the data and the error detection code.

  FIG. 4 shows an example of a data frame transmitted by the transmitting node. The data frame includes a data field, arbitration, control, error detection code, and ACK field. In FIG. 4, the arbitration, control, and ACK fields are omitted.

  In one embodiment of the data frame shown in FIG. 4, the data field is 7 bytes and the error detection code is 1 byte. Compared to the data frame shown in FIG. 1, the data frame does not contain a counter value. That is, the amount of data that can be included in the data frame can be increased compared to the data frame shown in FIG. For this reason, communication load can be reduced. This is because the ratio of error detection codes for confirming the certainty of the data can be reduced with respect to the amount of data that can be included in the data frame.

  A communication node that receives data (hereinafter referred to as “receiving node”) determines whether the data included in the received data frame is correct based on the error detection code included in the data frame from the transmitting node. Whether the reception order is correct can be confirmed.

  The receiving node uses the seed and received data (hereinafter referred to as “data”) when calculating the error detection code. Specifically, the counter value of the counter is used as a seed. The counter value of the counter may represent the data reception order. In the case of representing the order of data reception, the counter value changes as data is received. For example, the counter value of the counter changes as data is received. In the embodiment of the communication system, a case where the counter value increases by 1 as data is received will be described. Specifically, every time one frame is received, the counter value increases by one. The change in the counter value can be set as appropriate. By checking whether the data is correct, it is possible to check whether the data is garbled.

  When a cyclic code is used as the error detection code, one byte may be used as the cyclic code at the transmission node. For example, when 8 bytes are prepared for the data field and the error detection code, one of the 8 bytes may be used as a cyclic code. The receiving node can check whether the received data is correct and whether the reception order of the received data is correct using the cyclic code. If either or both of data anomalies from the transmitting node and / or an order of transmission has occurred, based on the value of the cyclic code included in the data from the transmitting node, the data from the transmitting node, and the receiving order It does not match the calculated cyclic code value. For this reason, the receiving node can detect the data abnormality of the data from the transmission node and / or the abnormality of the reception order by checking the cyclic code. That is, the transmitting node can make the receiving node check whether the order of data included in the data frame from the transmitting node is correct without including the counter value in the data frame. That is, it is possible to reduce the amount of data for confirming whether the data included in the received data frame is correct and whether the order of the data is correct. Accordingly, since the field used for storing the counter value can be used for data transmission, the communication efficiency can be improved.

  Since the receiving node can check whether or not the received data is correct and whether or not the order of the data is correct, the safety of the communication system with high ASIL (Automatic Safety Integrity Level) is ensured for the safety of the communication system function. It is possible to ensure safety.

  All systems are classified into multiple safety measures according to their risk. This measure is called ASIL in ISO WD26262. Depending on ASIL, the system is required to introduce various methods in order to reduce the possibility of risk occurrence. On the transmission side, a cyclic code is calculated using the counter value and data, and a data frame with the cyclic code added to the data is transmitted. On the receiving side, error detection is performed based on the cyclic code. By introducing the above method, the receiving side can confirm whether the received data is correct and whether the reception order of the data is correct.

The communication nodes 100 ₁ , 100 ₂ , 100 ₃ , and 100 ₄ may transmit / receive data modulated by the ASK scheme, or may transmit / receive data modulated by the OFDM scheme. Data modulated by another communication method may be transmitted and received. Whether data modulated by the ASK scheme or data modulated by the OFDM scheme is transmitted / received may be set according to the position where the communication node 100 _n is mounted.

<Communication node 100 _n >
The communication node 100 _n transmits and receives data to and from other communication nodes connected to the communication node 100 _n .

The communication node 100 _n uses the data and the counter value to calculate an error detection code. The communication node 100 _n creates a data frame including the data and the error detection code. The communication node 100 _n transmits a data frame.

Also, the communication node 100 _n receives a data frame from another communication node connected to the communication node 100 _n . The communication node 100 _n performs error detection based on data frames from other communication nodes.

If no error is detected in the data included in the data frame from another communication node as a result of the error detection, the communication node 100 _n may perform processing according to the data. This is because if no error is detected, it can be determined that the data included in the received data frame is correct and the transmission order is correct.

On the other hand, if an error is detected in the transmission data from another communication node as a result of the error detection, the communication node 100 _n may discard the transmission data or make a retransmission request. May be.

Figure 5 shows an embodiment of the communication node 100 _n. FIG. 5 mainly shows a hardware configuration.

The communication node 100 _n has a microprocessor (MPU: Micro-Processing Unit) 102. MPU102 communicates node 100 _n overall control.

The communication node 100 _n has a communication module 104. The communication module 104 communicates with the communication module 104 of another communication node. For example, communication is performed according to a predetermined communication protocol. The communication module 104 may perform modulation using the ASK method or may perform modulation using the OFDM method. Further, the communication module 104 may perform modulation using another communication method. Further, the communication module 104 may demodulate a signal modulated by the ASK method, or may demodulate a signal modulated by the OFDM method. In addition, the communication module 104 may demodulate a signal modulated by another communication method.

The communication node 100 _n includes a storage unit 106. The storage unit 106 stores a program for causing the MPU 102 to function as the communication node 100 _n .

  The MPU 102, the communication module 104, and the storage unit 106 are connected to each other via a bus 50.

<Function of the communication node 100 _n>
FIG. 6 shows the function of the communication node 100 _n . FIG. 6 mainly shows functions executed by the MPU 102. That is, when the MPU 102 functions according to software (program) stored in the storage unit 106, the function shown in FIG. 6 is executed. Further, the function shown in FIG. 6 may be executed by the function of the MPU 102 according to the software (firmware) stored in the MPU 102.

  The MPU 102 functions as an error detection code calculation unit 1022, a counter 1024, a transmission control unit 1026, an error detection unit 1028, and a signal processing unit 1030.

  Hereinafter, a case where a data frame is transmitted and a case where a data frame is received will be described separately.

The communication node 100 _n may have both functions of transmitting a data frame and receiving a data frame. In addition, the communication node 100 _n may have one of a function of transmitting a data frame and a function of receiving a data frame. That is, the communication node 100 _n may have a function of transmitting a data frame. The communication node 100 _n may have a function of receiving a data frame.

<When sending data frames>
Data is input to the error detection code calculation unit 1022. The error detection code calculation unit 1022 acquires a counter value indicating the transmission order from the counter 1024, and calculates an error detection code based on the counter value and data. Error detection code calculation section 1022 inputs an error detection code (hereinafter referred to as “first error detection code”) to transmission control section 1026. Specifically, the error detection code calculation unit 1022 uses the counter value as a seed value to calculate a cyclic code based on the seed value and a preset polynomial.

  Transmission control unit 1026 is connected to error detection code calculation unit 1022. Data is input to the transmission control unit 1026. The transmission control unit 1026 creates a data frame including the data and the first error detection code from the error detection code calculation unit 1022. The first error detection code is calculated based on the data. The transmission control unit 1026 performs control to transmit a data frame from the communication module 104. The data frame is transmitted from the communication module 104 according to control by the transmission control unit 1026.

<When receiving data frames>
A data frame from another communication node 100 _n is input from the communication module 104 to the error detection code calculation unit 1022. The error detection code calculation unit 1022 acquires a counter value indicating the reception order from the counter 1024, and calculates an error detection code based on the counter value and data included in the data frame. Specifically, the error detection code calculation unit 1022 uses the counter value as a seed value, and calculates an error detection code based on the seed value and a preset polynomial. The error detection code calculation unit 1022 inputs an error detection code (hereinafter referred to as “second error detection code”) to the error detection unit 1028.

The counter 1024 is connected to the error detection code calculation unit 1022. The counter 1024 counts data frames. Specifically, the counter value is incremented by 1 when a data frame is transmitted to another communication node. A counter value is prepared for each data frame to other communication nodes. Further, upon receiving a data frame from another communication node 100 _n, the counter value is incremented by one. For each data frame from the communication node 100 _n, the counter value is provided. Further, when the counter value increases to a predetermined value, it may be reset. That is, the range of the counter value is set in advance. By setting the range of the counter value in advance, it is possible to prevent the counter value from increasing to infinity.

  In one embodiment of the communication system, a case will be described in which the counter value increases from 0 to 15 and is reset to 0 when it reaches 16. Which value is reset can be set as appropriate. The counter 1024 inputs the counter value to the error detection code calculation unit 1022 in response to a request for the counter value from the error detection code calculation unit 1022. The error detection code calculation unit 1022 requests a counter value at the time of data frame transmission and reception.

  The error detection unit 1028 is connected to the communication module 104 and the error detection code calculation unit 1022. Data frames from other communication nodes are input from the communication module 104 to the error detection unit 1028. The error detection unit 1028 determines whether or not the first error detection code included in the data frame from the communication module 104 and the second error detection code from the error detection code calculation unit 1022 are equal, in other words, match. It is determined whether or not.

  When the first error detection code included in the transmission data from the communication module 104 is equal to the second error detection code from the error detection code calculation unit 1022, the error detection unit 1028 sends a signal processing unit 1030 to the signal processing unit 1030. Notify that no error was detected.

  On the other hand, when the error detection unit 1028 does not equal the calculation result of the first error detection code included in the data from the communication module 104 and the second error detection code from the error detection code calculation unit 1022, The error detection code calculation unit 1022 is notified that an error has been detected.

  When the error detection code calculation unit 1022 is notified that an error has been detected from the error detection unit 1028, the error detection code calculation unit 1022 determines the second value based on the counter value different from the previous counter value and the data included in the data frame. An error detection code is calculated. The error detection code calculation unit 1022 inputs the calculation result of the second error detection code to the error detection unit 1028.

  The error detection unit 1028 again determines whether or not the first error detection code included in the data frame from the communication module 104 is equal to the second error detection code from the error detection code calculation unit 1022.

  When the first error detection code included in the data frame from the communication module 104 is equal to the second error detection code from the error detection code calculation unit 1022, the error detection unit 1028 sends a signal processing unit 1030 to the signal processing unit 1030. Notify that no error was detected. In this case, it is determined that the order of the received data is incorrect.

  On the other hand, if the first error detection code included in the data frame from the communication module 104 and the second error detection code from the error detection code calculation unit 1022 are not equal, the error detection unit 1028 detects an error. The code calculation unit 1022 is notified that an error has been detected. The error detection code calculation unit 1022 performs the same process again when notified from the error detection unit 1028 that an error has been detected. If all the second error detection codes calculated for all counter values included in the preset counter value range are not equal to the first error detection code, it is determined that there is an error in the data. . In this case, the error detection unit 1028 notifies the signal processing unit 1030 that there is an error in the data.

  The signal processing unit 1030 is connected to the communication module 104 and the error detection unit 1028. Data frames from other communication nodes are input from the communication module 104 to the signal processing unit 1030. When notified from the error detection unit 1028 that an error has not been detected, the signal processing unit 1030 performs processing according to the data included in the data frame from the communication module 104.

  On the other hand, when notified from the error detection unit 1028 that an error has been detected, the signal processing unit 1030 may discard the data frame from the communication module 104 or transmit the data frame. You may make it request | require resending with respect to a 2nd communication node.

<Operation of Communication Node 100 _n (Part 1)>
FIG. 7 shows an embodiment of the operation of the communication node 100 _n .

FIG. 7 shows a process in which a data frame is transmitted by the communication node 100 _n .

In step S702, the communication node 100 _n, the data to be transmitted is generated.

  In step S704, the counter 1024 increments a counter value indicating the transmission order. For example, the counter 1024 increments the counter value by one. 1 is an example, and the setting can be changed as appropriate. However, the amount of increase in the counter of the transmitting node is equal to the amount of increase in the counter of the receiving node that receives the data frame from the transmitting node.

  In step S706, the error detection code calculation unit 1022 calculates an error detection code based on the data generated in step S702 and the counter value increased in step S704. Specifically, the error detection code calculation unit 1022 calculates an error detection code based on a preset polynomial using the counter value as a seed. The polynomial used by the error detection code calculation unit 1022 of the transmission node is equal to the polynomial used by the error detection code calculation unit 1022 of the reception node that receives transmission data from the transmission node.

  In step S708, the transmission control unit 1026 creates a data frame including the data and the error detection code obtained by the calculation in step 706. The transmission control unit 1026 creates the data frame shown in FIG. 4 by adding an error detection code to the data. In the data frame shown in FIG. 4, the data is represented by data 1 -data 7.

  In step S710, the transmission control unit 1026 transmits the data frame created in step S708. Under the control of the transmission control unit 1026, the data frame is transmitted from the communication module 104 to another communication node.

<Operation of communication node 100 _n (part 2)>
Figure 8 illustrates one embodiment of the operation of the communication node 100 _n.

FIG. 8 shows a process in which a data frame from another communication node is received by the communication node 100 _n .

  In step S802, a data frame from another communication node 100 is received.

  In step S804, the error detection code calculation unit 1022 determines whether or not the data frame received in step S802 has been received for the first time. For example, the error detection code calculation unit 1022 determines whether or not the data frame is first received after the ignition is turned on.

  If it is determined in step S806 that the data frame is received for the first time, the error detection code calculation unit 1022 sets the seed value to an initial value. This is because the previous value does not exist in the counter. For example, the error detection code calculation unit 1022 sets the seed value to zero (initial value). When the data frame is received for the first time, by setting the seed value to the initial value, processing can be performed even when the counter value is unknown.

  In step S808, the error detection code calculation unit 1022 calculates a second error detection code based on the data included in the data frame and the seed value. Specifically, the error detection code calculation unit 1022 calculates a cyclic code based on the seed value and a preset polynomial.

  In step S810, the error detection code calculation unit 1022 increases the seed value. For example, the error detection code calculation unit 1022 increases the seed value by one. The 1 is an example and can be changed as appropriate. However, the increase amount in the error detection code calculation unit 1022 of the transmission node is equal to the increase amount in the error detection code calculation unit 1022 of the reception node that receives the data frame from the transmission node.

  In step S812, the error detection code calculation unit 1022 determines whether or not the seed value increased in step S810 is larger than 16. This is because when the seed value is larger than 16, it is reset.

  In step S814, if it is determined in step S812 that the seed value is 16 or less, the first error detection code included in the data frame matches the second error detection code obtained by the calculation in step S808. It is determined whether or not to do so.

  In step S816, if it is determined in step S812 that the seed value is greater than 16, the error detection unit 1028 determines that the data included in the data frame has an error. In this case, the signal processing unit 1030 may discard the data frame or may make a retransmission request to another node. When a retransmission request is made, the same sequence as the first reception is executed when the next data frame is received.

  In step S818, if it is determined that the first error detection code included in the data frame in step S814 matches the second error detection code obtained by the calculation in step S808, the signal processing unit 1030 It is determined whether or not the frame is received for the first time.

  In step S820, if it is determined in step S818 that the data frame is received for the first time, the signal processing unit 1030 performs processing based on the data included in the data frame.

  In step S822, the error detection code calculation unit 1022 decreases the seed value by 1 (seed value-1) and sets it to the counter 1024 as a counter value in preparation for the next data frame reception. After executing the process in step S822, the process returns to step S802. After the next reception, processing is executed based on the previously searched counter value. Specifically, the counter is incremented for each reception.

  On the other hand, if it is determined in step S814 that the first error detection code included in the data frame does not match the second error detection code obtained by the calculation in step S808, the process returns to step S808. By returning to step S808, the second error detection code is calculated using the seed value increased in step S810, and the same processing is performed.

  In step S824, if it is determined in step S818 that the data frame is not received for the first time, the error detection code calculation unit 1022 decrements the counter value by 1 in order to prepare for reception of the next data frame (seeding). Value-1) and set in the counter 1024.

  In step S826, the signal processing unit 1030 determines that there is an order error in the data. For example, the signal processing unit 1030 determines that there is a counter abnormality and / or a reception order abnormality. After executing the process in step S826, the process returns to step S802.

  In step S828, if it is determined in step S804 that the data frame has not been received for the first time, the counter 1024 increments the counter value indicating the reception order. For example, the counter 1024 increments the counter value by one. 1 is an example, and the setting can be changed as appropriate. However, the amount of increase in the counter of the transmitting node is equal to the amount of increase in the counter of the receiving node that receives the data frame from the transmitting node.

  In step S830, error detection code calculation section 1022 calculates a second error detection code based on the data included in the data frame received in step S802 and the counter value incremented in step S828. Specifically, the error detection code calculation unit 1022 calculates a second error detection code based on a preset polynomial using the counter value as a seed. The polynomial used by the error detection code calculation unit 1022 of the transmission node is equal to the polynomial used by the error detection code calculation unit 1022 of the reception node that receives the data frame from the transmission node.

  In step S832, the error detection unit 1030 determines whether or not the first error detection code included in the data frame received in step S802 matches the second error detection code obtained by the calculation in step S830. Determined.

  In step S834, when it is determined that the first error detection code included in the data frame received in step S802 matches the second error detection code obtained by the calculation in step S830, the signal processing unit 1030 The processing is performed based on the data included in the data frame. After executing the process in step S834, the process returns to step S802. After the next reception, processing is executed based on the previously searched counter value. Specifically, the counter is incremented for each reception.

  On the other hand, if it is determined that the first error detection code included in the data frame received in step S802 does not match the second error detection code obtained by the calculation in step S830, the process proceeds to step S806. By transitioning to step S806, the processing of steps S806 to S826 is executed. That is, the seed value is changed, and it is determined whether or not the calculation results of the first error detection code and the second error detection code match. If the seed value is greater than 15 but does not match, it is determined that there is an error in the data included in the data frame.

  If the seed values do not exceed 15 and match, it is determined that the counter is abnormal (reception order abnormality).

  According to the communication system according to the present embodiment, the transmission node uses the counter value as a seed based on the data to be transmitted to the reception node and the counter value indicating the transmission order of the data. And a data frame including the first error detection code and the data is transmitted. Since the data frame does not include a counter value indicating the data transmission order, the amount of data that can be transmitted in the data frame can be increased.

  Based on the data included in the data frame and the counter value indicating the reception order of the data, the receiving node calculates a second error detection code using the counter value as a seed, It is determined whether or not they match. By determining whether or not the first error detection code and the second error detection code match, it is determined whether or not the data included in the data frame has an error and whether or not the reception order is correct it can.

  Although the present invention has been described above with reference to specific embodiments, each embodiment is merely an example, and those skilled in the art will understand various variations, modifications, alternatives, substitutions, and the like. I will. For convenience of explanation, an apparatus according to an embodiment of the present invention has been described using a functional block diagram, but such an apparatus may be realized by hardware, software, or a combination thereof. The present invention is not limited to the above-described embodiments, and various variations, modifications, alternatives, substitutions, and the like are included without departing from the spirit of the present invention.

50 Communication bus 100 _n (n is an integer of n> 0) Communication node 150 Communication bus 102 MPU
DESCRIPTION OF SYMBOLS 104 Communication module 106 Memory | storage part 1022 Error detection code | cord | chord calculation part 1024 Counter 1026 Transmission control part 1028 Error detection part 1030 Signal processing part

Claims (10)

A communication node included in the communication system,
A first error detection code computing unit that calculates a first error detection code using the counter value as a seed based on data to be transmitted to another communication node and a counter value representing the transmission order of the data;
A communication node, comprising: a transmission control unit that performs control to transmit a data frame including the first error detection code calculated by the first error detection code calculation unit and the data to the other communication node. . A communication module for receiving data frames from other communication nodes;
Second error detection for calculating a second error detection code using the counter value as a seed based on data included in the data frame received by the communication module and a counter value indicating the reception order of the data A sign calculation unit;
An error detection unit that determines whether or not the second error detection code calculated by the second error detection code calculation unit matches the first error detection code included in the data frame;
The communication node according to claim 1, further comprising: a signal processing unit that performs processing according to data included in the data frame based on a determination result by the error detection unit. When the second error detection code calculated by the second error detection code calculator does not match the first error detection code included in the data frame, the second error detection code calculator is The counter value is sequentially changed, and the second error detection code is calculated using the counter value as a seed,
The error detection unit determines whether or not the second error detection code calculated by the second error detection code calculation unit matches the first error detection code included in the data frame; The communication node according to claim 2.   The error detection unit is configured such that all of the second error detection codes calculated for all counter values included in a preset counter value range do not match the first error detection code included in the data frame. The communication node according to claim 3, wherein the data included in the data frame received by the communication module is determined to have an error.   When the second error detection code calculated for all the counter values included in the preset counter value range matches the first error detection code included in the data frame, the signal processing is performed. The communication node according to claim 3 or 4, wherein the unit determines that there is an error in the reception order of the data frames based on the determination result by the error detection unit. The second error detection code calculation unit sequentially changes the counter value when the data frame received by the communication module is a data frame received for the first time, and uses the counter value as a seed. Error detection code of
The error detection unit determines whether or not the second error detection code calculated by the second error detection code calculation unit matches the first error detection code included in the data frame; The communication node according to any one of claims 2 to 5.   The error detection unit is configured such that all of the second error detection codes calculated for all counter values included in a preset counter value range do not match the first error detection code included in the data frame. The communication node according to claim 6, wherein the data included in the data frame received by the communication module is determined to have an error. A communication node included in the communication system,
A communication module for receiving data frames from other communication nodes;
An error detection code calculation unit that calculates an error detection code using the counter value as a seed based on data included in the data frame received by the communication module and a counter value indicating the reception order of the data;
An error detection unit that determines whether or not the error detection code calculated by the error detection code calculation unit and the error detection code included in the data frame match;
And a signal processing unit that performs processing according to data included in the data frame based on a determination result by the error detection unit. A communication system having a plurality of communication nodes,
The first communication node is
A first error detection code computing unit that calculates a first error detection code using the counter value as a seed based on data to be transmitted to the second communication node and a counter value representing the transmission order of the data; ,
A transmission control unit that performs control to transmit a data frame including the first error detection code calculated by the first error detection code calculation unit and the data to the second communication node;
The second communication node is
A communication module for receiving a data frame from the first communication node;
Second error detection for calculating a second error detection code using the counter value as a seed based on data included in the data frame received by the communication module and a counter value indicating the reception order of the data A sign calculation unit;
An error detection unit that determines whether or not the second error detection code calculated by the second error detection code calculation unit matches the first error detection code included in the data frame;
A signal processing unit that performs processing according to data included in the data frame based on a determination result by the error detection unit. A communication method in a communication system having a plurality of communication nodes,
The first communication node is
Based on the data to be transmitted to the second communication node and the counter value representing the transmission order of the data, the first error detection code is calculated using the counter value as a seed,
Performing control to transmit a data frame including the first error detection code and the data to the second communication node;
The second communication node is
Receiving a data frame from the first communication node;
Based on the data included in the data frame and the counter value representing the reception order of the data, the second error detection code is calculated using the counter value as a seed,
Determining whether the second error detection code and the first error detection code included in the data frame match;
A communication method for performing processing according to data included in the data frame based on the determination result.

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