Data transmission and reception system

Abstract

To more appropriately determine whether received data is abnormal when data is irregularly transmitted in response to an event that occurs irregularly.SOLUTION: A data transmission and reception system includes a transmitting device that transmits data and a receiving device that receives the data, and the transmitting device transmits data including information on the transmission interval, which is the time interval from a predetermined past transmission to the current transmission, and when the receiving device receives the data, the receiving device determines whether the received data is abnormal by comparing the information on the reception interval, which is the time interval from a predetermined past reception to the current reception, with the information on the transmission interval included in the received data.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a data transmission and reception system. [Background technology]

[0002] A conventional data transmission / reception system of this type includes a transmitting device that transmits data and a receiving device that receives data via a network bus, and the transmitting device transmits data at predetermined intervals (see, for example, Patent Document 1). In this system, if the reception interval for receiving data is shorter than the predetermined interval stored in a filter table, and the next data is received within the predetermined interval, the receiving device determines that an abnormality has occurred in the previously received data. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-146868 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-described data transmission and reception system, when data is transmitted irregularly in response to an event that occurs irregularly, the received data may be normal even if the data reception cycle is shorter than the predetermined cycle, and in this case, the received data may be erroneously determined to be abnormal data.

[0005] The data transmission / reception system of the present disclosure has a primary objective of more accurately determining whether or not received data is abnormal when data is transmitted irregularly in response to events that occur irregularly. [Means for solving the problem]

[0006] The data transmission and reception system of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The data transmission and reception system of the present disclosure includes: A data transmission / reception system including a transmitting device that transmits data and a receiving device that receives data, the transmitting device transmits data including information on a transmission interval, which is a time interval from a predetermined past transmission to a current transmission; When the receiving device receives data, it compares information about the reception interval, which is the time interval from the predetermined previous reception to the current reception, with information about the transmission interval included in the received data to determine whether the received data is abnormal. The gist of this is as follows.

[0008] In the data transmission and reception system disclosed herein, a transmitting device transmits data including information on a transmission interval, which is the time interval between a predetermined previous transmission and a current transmission. When the receiving device receives the data, the receiving device compares the information on the reception interval, which is the time interval between a predetermined previous reception and a current reception, with the information on the transmission interval included in the received data to determine whether the received data is abnormal. As a result, when data is transmitted irregularly in response to an event that occurs irregularly, it is possible to more accurately determine whether the received data is abnormal. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an outline of the configuration of a data transmission / reception system 20 according to an embodiment of the present disclosure. [Figure 2] 4 is a flowchart showing an example of a determination routine executed by a reception data processing unit 34 of an ECU 32. [Figure 3] 10 is an explanatory diagram illustrating an example of the relationship between the regular transmission cycle Tc, the reception interval Tri, and the transmission interval Tsi depending on whether or not spoofed transmission is present. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a configuration diagram showing an outline of the configuration of a data transmission and reception system 20 according to an embodiment of the present disclosure. The data transmission and reception system 20 is mounted on, for example, an automobile equipped with drive devices such as an engine, a motor, and a transmission, and includes an electronic control unit (hereinafter referred to as "ECU") (data receiving device) 22 and an ECU (data transmitting device) 32.

[0011] Although not shown, the ECU 22 is configured as a microcomputer having a CPU, ROM, RAM, flash memory, a CAN (Controller Area Network, registered trademark) controller, a CAN transceiver, input / output ports, and a communication port, and is connected to a CAN bus 28 connected to the communication port. The ECU 22 includes a transmission data processing unit 24 and a transmission cycle calculation unit 26. The transmission data processing unit 24 performs periodic transmission, in which a data frame (data) D including detection values ​​from various sensors and the like is periodically transmitted to the CAN bus 28 at a predetermined periodic transmission cycle Tc, and event transmission, in which a data frame D including detection values ​​is transmitted to the CAN bus 28 every time a detection value is input by various sensors and the like. The data frame D is configured in a standard format for CAN communication, including, for example, an 11-bit frame ID indicating the type of detection value, the identification of the transmitting node, and the priority of communication arbitration, a data field including the detection value and the transmission interval Tsi from the transmission period calculation unit 26, SOF (Start of Frame), RTR (Remote Transmission Request), control field, CRC (Cyclic Redundancy Check) field, ACK slot, ACK delimiter, EOF (End of Frame), and ITM (Intermission). When the transmission data processing unit 24 transmits the data frame D, the transmission period calculation unit 26 calculates the difference ΔTs between the transmission time Ts and the previous transmission time Tspre, which is the time when the previous data frame D was transmitted, sets the calculated ΔTs as the transmission interval Tsi, and outputs it to the transmission data processing unit 24.

[0012] Although not shown, the ECU 32 is configured as a microcomputer having a CPU, ROM, RAM, flash memory, a CAN controller, a CAN transceiver, input / output ports, and a communication port, and is connected to the CAN bus 28 connected to the communication port. The ECU 32 includes a received data processing unit 34, a received cycle calculation unit 36, and a frame table storage unit 38. The received data processing unit 34 receives data frames D transmitted to the CAN bus 28 and performs various processes. When the received data processing unit 34 receives a data frame D, the received cycle calculation unit 36 ​​calculates the difference ΔTr between the received time Tr and the previous received time Trpre, which is the time when the previous data frame D was received, and sets the calculated ΔTr as the reception interval Tri. The frame table storage unit 38 stores frame table information indicating the relationship between multiple frame IDs and the regular transmission cycle Tc of data frames D including each frame ID.

[0013] Next, the operation of the data transmission / reception system 20 configured as described above will be described, in particular the operation when the ECU 32 determines whether the received data frame D is invalid. Figure 2 is a flowchart showing an example of a determination routine executed by the received data processing unit 34 of the ECU 32. This routine is executed when the received data processing unit 34 receives the data frame D transmitted to the CAN bus 28.

[0014] When this routine is executed, the received data processing unit 34 determines whether the frame ID included in the received data frame D exists in the frame table stored in the frame table storage unit 38 (S100). If the frame ID exists, the reception interval Tri is input from the reception cycle calculation unit 36 ​​(S110). Next, it determines whether the reception interval Tri matches the periodic transmission cycle Tc (S120). The periodic transmission cycle Tc is derived from the frame table information stored in the frame table storage unit 38 as the periodic transmission cycle Tc corresponding to the frame ID included in the received data frame D. When the received data frame D is periodically transmitted from the ECU 22, the reception interval Tri matches the periodic transmission cycle Tc. Therefore, S120 is a process for determining whether a regular data frame D has been received correctly from the ECU 22.

[0015] If the reception interval Tri and the regular transmission cycle Tc match in S120, it is determined that reception is normal (S140) and this routine ends. If reception is normal, the received data frame D is used for various calculations, control of the drive device, etc.

[0016] If the reception interval Tri and the regular transmission cycle Tc do not match in S120, it is determined that the received data frame D was not periodically transmitted from the ECU 22, and then it is determined whether at least one of the following is true: the data field of the received data frame D includes the transmission interval Tsi, and the reception interval Tri is shorter than the transmission interval Tsi included in the data field of the received data frame D (S130). When the data frame D is transmitted from the ECU 22 as an event transmission, the data field of the received data frame D includes the transmission interval Tsi, and the reception interval Tri and the transmission interval Tsi match, or the reception interval Tri is slightly longer than the transmission interval Tsi. Therefore, S130 is a process for determining whether the received data frame D is a data frame Dic transmitted as a result of an event transmission.

[0017] If the data field of the received data frame D contains the transmission interval Tsi and the reception interval Tri is equal to or greater than the transmission interval Tsi, it is determined that the event was transmitted from the ECU 22 and was received normally (S140), and this routine is terminated.

[0018] If the data field of the received data frame D does not contain the transmission interval Tsi, or if the reception interval Tri is less than the transmission interval Tsi, the received data frame D is determined to be neither a periodic nor an event transmission from the ECU 22, but a data frame Dic transmitted by spoofing from an unauthorized device that is not permitted to transmit data frames D to the CAN bus 28, and it is determined that a spoofing anomaly has occurred (S150), and this routine is terminated.

[0019] FIG. 3 is an explanatory diagram illustrating an example of the relationship between the periodic transmission cycle Tc, the reception interval Tri, and the transmission interval Tsi depending on whether or not spoofed transmission occurs. Data frames D0, D1, and D3 are data frames transmitted from the ECU 22 by periodic transmission at the periodic transmission cycle Tc. Data frame D2 is a data frame transmitted from the ECU 22 by event transmission. Data frames Dic1 to Dic3 are unauthorized data frames transmitted to the CAN bus 28 from an unauthorized device between the transmission of data frame D1 and the transmission of data frame D2. In the diagram, "normal" indicates that the received data processing unit 34 has determined that the data has been received normally. "abnormal" indicates that the received data processing unit 34 has determined that a spoofing abnormality has occurred.

[0020] When there is no spoofed transmission, if the transmission from the ECU 22 is a regular transmission (time t1), the reception interval Tri (reception interval Tri1 between data frames D0 and D1), which is the time interval from the previous reception to the current reception, matches the regular transmission cycle Tc, so the reception data processing unit 34 determines that the reception is normal.If the transmission from the ECU 22 is an event transmission (time t2), the reception interval Tri (reception interval Tri2 between data frames D1 and D2) does not match the regular transmission cycle Tc, and the reception interval Tri matches the transmission interval Tsi (transmission interval Tsi2) included in the data frame D, so the reception data processing unit 34 determines that the reception is normal.

[0021] When spoofed transmission is detected, the received data processing unit 34 receives data frames Dic1 to Dic3 from the unauthorized device that is transmitting the spoofed data, along with data frames D1 to D3 transmitted from the ECU 22. The data frames Dic1 to Dic3 from the unauthorized device may have little correlation between the transmission interval Tsi included in the data field and the reception intervals Tria to Trid between the data frames D received before and after them by the ECU 32, or the data field may not contain information about the transmission interval Tsi. Therefore, when the data field of the received data frame D does not contain the transmission interval Tsi, or when the reception interval Tri is shorter than the transmission interval Tsi, it can be determined that the received data frame D is a data frame Dic transmitted by spoofing. Note that in FIG. 3, the reception interval Trid between the reception of data frame Dic3 and the reception of data frame D2 is different from the regular transmission cycle Tc and is shorter than the transmission interval Tsi2 included in data frame D2. Therefore, the received data processing unit 34 erroneously determines that the data frame D2 is a spoofed data frame, even though it is actually a data frame transmitted from the ECU 22. However, such an erroneous determination is permitted.

[0022] If a spoofing error occurs, the received data frame D is discarded. This prevents the data frame D in which a spoofing error occurs from being used for various calculations or for controlling the drive device, allowing for more appropriate calculations and control of the drive device.

[0023] If the frame ID included in the data frame D received in S100 does not exist in the frame table stored in the frame table storage unit 38, it is determined that an ID abnormality, which is an abnormality related to the frame ID, has occurred (S160), and this routine ends. In this case, too, the received data frame D is discarded. This prevents the data frame D with an ID abnormality from being used in various calculations or control of the drive device, allowing for more appropriate calculations and control of the drive device.

[0024] According to the data transmission / reception system 20 of this embodiment described above, the ECU 22 transmits a data frame D including information on the transmission interval Tsi, which is the time interval between the previous transmission and the current transmission, and when the ECU 32 receives the data frame D, it determines whether the received data frame D is abnormal data based on whether the reception interval Tri, which is the time interval between the previous reception and the current reception, matches the regular transmission cycle Tc, whether the received data frame D includes information on the transmission interval Tsi, and whether the reception interval Tri is shorter than the transmission interval Tsi included in the data frame D.Therefore, when the ECU 22 executes event transmission, it can more accurately determine whether the received data frame is abnormal.

[0025] In the above-described embodiment, the transmission interval Tsi is the time interval from the immediately previous transmission to the current transmission, and the reception interval Tri is the time interval from the immediately previous reception to the current reception. However, the transmission interval Tsi may be the time interval from the transmission two or more times prior to the current transmission to the current transmission, and the reception interval Tri may be the time interval from the reception two or more times prior to the current reception to the current reception.

[0026] In the above-described embodiment, the data frame D is configured as a standard format for CAN communication, but it may also be configured as an extended format for CAN communication, or as a format for a communication protocol different from CAN communication.

[0027] In the above-described embodiment, the ECU 32 determines in S120 whether the reception interval Tri, which is the time interval from the previous reception to the current reception, matches the periodic transmission cycle Tc. However, if the ECU 22 does not perform periodic transmission, S120 does not need to be executed. Also, in S130, it is determined whether the received data frame D includes information on the transmission interval Tsi. However, it is not necessary to determine whether the received data frame D includes information on the transmission interval Tsi. It is sufficient to determine whether the received data frame D contains abnormal data by comparing information on the reception interval Tri, which is the time interval from the previous reception to the current reception, with information on the transmission interval Tsi included in the received data frame D.

[0028] In the embodiment described above, it is determined whether the frame ID included in the data frame D received in S100 exists in the frame table stored in the frame table storage unit 38, but S100 does not have to be executed.

[0029] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be described below. In the embodiment, the ECU 22 corresponds to the "transmitting device," and the ECU 32 corresponds to the "receiving device."

[0030] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0031] The above describes the forms for implementing the present disclosure using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0032] The present disclosure is applicable to the manufacturing industry of data transmission / reception systems, etc. [Explanation of symbols]

[0033] 20 data transmission / reception system, 22, 32 electronic control unit (ECU), 24 transmission data processing unit, 26 transmission period calculation unit, 34 reception data processing unit, 36 reception period calculation unit, 38 frame table storage unit.

Claims

[Claim 1] A data transmission / reception system including a transmitting device that transmits data and a receiving device that receives data, the transmitting device transmits data including information on a transmission interval, which is a time interval from a predetermined past transmission to a current transmission; When the receiving device receives data, it compares information about the reception interval, which is the time interval from the predetermined previous reception to the current reception, with information about the transmission interval included in the received data to determine whether the received data is abnormal. Data transmission and reception system.

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