In-vehicle communication system and in-vehicle communication method

Abstract

The present disclosure proposes an onboard communication system (see fig. 2) that successively transmits, through one round of communication, data configured from a plurality of frames from a transmission-side device to a reception-side device in order to enable the occurrence of missed data captures on the reception side to be reduced. The transmission-side device executes a process for performing initial communication with the reception-side device and confirming a response time achieved by the reception-side device, a process for determining the form of successive transmissions of data to the reception-side device on the basis of the response time, and a process for successively transmitting data in frame units to the reception-side device in accordance with the determined form of successive transmissions.

Description

[Technical Field]

[0001] The present disclosure relates to an in-vehicle communication system and an in-vehicle communication method. [Background technology]

[0002] In an in-vehicle control system, for example, in a reprogramming process, a continuous data transmission process is executed from a reprogramming tool (program writing device) to an ECU (Electronic Control Unit: an in-vehicle control device). In recent years, to strengthen security, there has been an increase in cases where a large amount of data is transmitted (continuously transmitted in frame units) not only from the tool but also from the ECU to the tool or another ECU.

[0003] For example, Non-Patent Document 1 specifies that before communication is established between the sending and receiving sides, the transmission interval for continuous data transmission is predetermined as an arbitrary fixed value depending on the model of the receiving device, and continuous transmission processing is performed at the transmission interval of that fixed value. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] ISO 15765-2 Third edition 2016-04-01,”Road vehicles - Diagnostic communication over Controller Area Network (DoCAN) - Part 2: Transport protocol and network layer services” Summary of the Invention [Problem to be solved by the invention]

[0005] However, if continuous transmission processing is performed at a fixed transmission interval determined before communication begins, as with the technology specified in ISO15765-2, when the processing load on the receiving device is high, the receiving processing may not be able to keep up, and transmitted data may be missed. In view of such circumstances, the present disclosure proposes a technique that makes it possible to reduce the occurrence of data loss on the receiving side. [Means for solving the problem]

[0006] In order to solve the above problem, the present disclosure proposes, as an example, an in-vehicle communication system that continuously transmits data consisting of multiple frames from a transmitting device to a receiving device in a single communication, in which the transmitting device performs an initial communication with the receiving device and performs the following processes: confirming the response time of the receiving device; determining a form of continuous transmission of the data to the receiving device based on the response time; and continuously transmitting the data to the receiving device in frame units in accordance with the determined form of continuous transmission.

[0007] Further features related to the present disclosure will become apparent from the description and accompanying drawings of this specification, and aspects of the present disclosure may be realized and realized by the elements and combinations of various elements and aspects set forth in the following detailed description and the appended claims. The descriptions herein are exemplary and illustrative only and are not intended to limit the scope or application of the present disclosure in any way. [Effects of the Invention]

[0008] According to the technology of the present disclosure, it is possible to reduce the occurrence of data loss on the receiving side. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing an example of a schematic configuration of an in-vehicle communication system 100 according to an embodiment of the present invention. [Figure 2]10A and 10B are diagrams for explaining an outline of determining a transmission interval during continuous data transmission according to the present embodiment. [Figure 3] 10 is a flowchart illustrating details of a continuous transmission process according to the present embodiment. [Figure 4] 10 is a diagram showing an example of how each parameter is stored in a storage device (for example, EEPROM 10113) on the transmitting side 201. FIG. [Figure 5] FIG. 10 is a diagram showing the current required response time (required response time 203 from sending FirstFrame to receiving FlowControl) and the current transmission interval (transmission interval 204 during continuous data transmission) determined from the above formula (1). [Figure 6] 4 is a flowchart for explaining a continuous transmission process that includes a process of recalculating and storing an average required response time and an average transmission interval in addition to the process of FIG. 3 . [Figure 7] FIG. 10 is a diagram illustrating the concept of retrying the continuous transmission process. [Figure 8] FIG. 10 is a diagram for explaining an outline of a continuous transmission process according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present disclosure discloses that, in an in-vehicle system, during communication between a transmitter and a receiver, the transmitter adaptively determines a continuous transmission format configured with a transmission interval and a transmission size used for continuous data transmission to the receiver, and executes continuous transmission of multiple frames (predetermined size) of data based on the determined format, thereby preventing data loss on the receiver.

[0011] Hereinafter, embodiments and examples of the present disclosure will be described with reference to the accompanying drawings. In the accompanying drawings, functionally identical elements may be designated by the same numerals. Note that the accompanying drawings show specific embodiments and implementation examples in accordance with the principles of the present disclosure, but these are intended to aid in understanding the present disclosure and are by no means to be used to interpret the present disclosure in a limiting manner.

[0012] Although the present embodiment has been described in sufficient detail to enable those skilled in the art to implement the present disclosure, it should be understood that other implementations and forms are possible, and that changes in configuration and structure and substitutions of various elements are possible without departing from the scope and spirit of the technical ideas of the present disclosure. Therefore, the following description should not be interpreted as being limited thereto.

[0013] <Configuration example of an in-vehicle communication system> Fig. 1 is a diagram showing a schematic configuration example of an in-vehicle communication system 100 according to this embodiment. In Fig. 1, the in-vehicle communication system 100 is configured by extracting only parts related to the technology of the present disclosure, but may also include elements other than those shown in Fig. 1.

[0014] The in-vehicle communication system 100 includes an ECU (in-vehicle control device) 101, which is set on the transmitting side in this embodiment, and a tool (reprogramming tool: program writing device) 102 and multiple ECUs 103_1 to 103_n, which are different from the transmitting-side ECU 101, which are set on the receiving side in this embodiment.

[0015] The ECU 101 includes an arithmetic unit (microcomputer) 1011, various ICs 1012, and a communication unit 1013. The arithmetic unit 1011 includes, as an internal storage device, at least one of an SRAM 10111, a flash memory 10112, and an EEPROM 10113. The SRAM 10111, the flash memory, and the EEPROM 10113 may be provided outside the arithmetic unit 1011. The ECU 101 may also be communicably connected to, for example, a server device (not shown) or an external storage device (not shown).

[0016] Similar to the ECU 101, the tool 102 includes, as internal components, an arithmetic unit 1021, various ICs 1022, and a communication unit 1023. The arithmetic unit 1021 includes, as an internal storage device, at least one of an SRAM 10211, a FLASH memory 10212, and an EEPROM 10213. Similarly to the ECU 101, the tool 102 may also be communicably connected to a server device (not shown) or an external storage device (not shown). The other plurality of ECUs 103_1 to 103_n different from the ECU 101 can also have the same internal configuration as the ECU 101.

[0017] <Outline of determining transmission interval> 2 is a diagram for explaining an outline of determination of a transmission interval when continuous data transmission is performed according to this embodiment. In this embodiment, in FIG. 2, the ECU 101 corresponds to a device on the transmitting side 201 (transmitting side device), and the tool 102 or any of the ECUs 103_1 to 103_n corresponds to a device on the receiving side 202 (receiving side device).

[0018] When transmitting data continuously, the transmitting side 201 sends a prior notification to the receiving side 202 that it will transmit continuously. The transmitting side 201 executes continuous transmission after receiving a permission notification (FlowControl, described below: permission for continuous transmission) corresponding to this prior notification from the receiving side 202. The period from this prior notification to approval is the "time required from data transmission to response reception (hereinafter referred to as the "prior notification response time" or "required response time") 203." This prior notification corresponds to the "FirstFrame," described below, and includes information on the specifications (method) of continuous transmission as communication data content, such as a notification (signal) to start continuous transmission, information on the number of messages to be transmitted, and information on the transmission (communication) format (the amount of data per transmission: for example, transmission in 64-byte units or 8-byte units). For example, the transmission (communication) format can be the standard format or extended format for CAN (Controller Area Network) communication.

[0019] When the transmitting side 201 receives an ACK from the receiving side 202, it calculates (detects) the advance notification response time (required response time) 203, and determines (estimates) the state (processing load state) of the receiving side 202 based on this, and calculates the "transmission interval 204 when continuously transmitting data." For example, if the advance notification response time 203 is longer than a predetermined time, it can be determined that the load on the receiving side 202 is heavy, and therefore the transmission interval 204 can be set longer. The method for determining the transmission interval 204 will be described in detail later. The transmitting side 201 transmits successive frames to the receiving side 202 repeatedly at the determined transmission interval 204 .

[0020] As described above, this embodiment differs from conventional technologies (for example, the above-mentioned ISO15765-2) in that in conventional technologies, the transmission interval is determined as a fixed value before communication starts and cannot be changed thereafter, in that the transmitting side 201 and the receiving side 202 give advance notice regarding continuous transmission, and the transmission interval 204 is adaptively determined based on the communication result, so that continuous transmission can be performed taking into account the state of the receiving side 202, and communication efficiency can be maximized.

[0021] <Details of continuous transmission process> 3 is a flowchart for explaining the details of the continuous transmission process according to this embodiment. The subject of operation of each step is the transmitting side 201, i.e., the ECU 101. However, since the technology of the present disclosure can also be implemented by the tool 102 as the transmitting side device, the subject of operation will be described below as the transmitting side 201.

[0022] (i) S301 The transmitting side 201 transmits a FirstFrame as a prior notification of continuous transmission to the receiving side 202. As described above, the FirstFrame includes information on the continuous transmission specifications.

[0023] (ii) S302 The transmitting side 201 waits until it receives FlowControl from the receiving side 202. If FlowControl has been received (Yes in S302), the process proceeds to S303.

[0024] (iii) S303 The transmitting side 201 calculates the required response time (advance notification response time 203) from the time of FirstFrame (FF) transmission and the time of FlowControl (FC) reception.

[0025] (iv) S304 The transmitting side 201 calculates the optimal transmission interval 204 based on the advance notification response time 203 calculated in S303. Here, the "optimal transmission interval" means at least a transmission interval that does not result in data being dropped (the time interval from one Consecutive Frame transmission to the next Consecutive Frame transmission), and is usually a shorter time than in the conventional case unless the processing load on the receiving side 202 is excessive.

[0026] (v) S305 The transmitting side 201 stores the required response time value calculated in S303 and the transmission interval value calculated in S304 in the EEPROM 10113. The storage destination is not limited to the EEPROM 10113, but may be the SRAM 1011, the flash memory 10112, or an external server device or external storage device (neither of which are shown) via a network.

[0027] In the internal storage device (for example, EEPROM 10113) where the data is saved, the storage area can be divided for each device on the receiving side 202, and the required response time value and the transmission interval value (each time they are calculated) can be stored.

[0028] (vi) S306 The transmitting side 201 transmits all consecutive frames (Consecutive Frames) to the receiving side 202 at the transmission interval calculated in S304.

[0029] (vii)S307 After transmitting all ConsecutiveFrames, the transmitting side 201 determines whether FlowControl has been received from the receiving side 202 within a predetermined time. If FlowControl has been received from the receiving side 202 within the predetermined time (Yes in S307), the continuous transmission process ends. On the other hand, if FlowControl has not been received from the receiving side 202 within the predetermined time (No in S307), it is determined that the continuous transmission process has ended in failure, and the process proceeds (returns) to S301. If the continuous transmission process has ended in failure, this means that the calculated transmission interval value was inappropriate. Therefore, the process returns to S301, and the process of determining the transmission interval is executed again.

[0030] <Saving parameters to a storage device> FIG. 4 shows an example of how each parameter is stored in a storage device (for example, EEPROM 10113) on the transmitting side 201. Here, each parameter can include, for example, the value of the required response time for each transmission and the value of the transmission interval for each successive transmission. Note that the past required response time (T av ) and the average value of the past transmission interval (IT av ) may be included.

[0031] As shown in FIG. 4, the EEPROM 10113 for storing parameters has areas for storing parameters for each of the tool 102 and ECUs 103_1 to 103_n. For example, for each of the reprogramming tool A 401, reprogramming tool B 402, and ECU1_403, areas X1 to Xn+2 are defined as areas for storing the past required response time values ​​for each device, and areas A1 to An+2 are defined as areas for storing the past transmission interval values ​​for each device. In this way, the EEPROM 10113 has areas X and A equal to the number of devices with which the transmitting side 201 may communicate. Here, only a reprogramming tool is shown as a tool, but areas for other tools (e.g., diagnostic tools) may also be provided. Furthermore, parameters can be managed by dividing the areas according to communication conditions (e.g., transmission (communication) format: one frame is 64 bytes or 8 bytes) for each receiving side (communication partner device).

[0032] As described above, the storage device can be an EEPROM 10113 inside the transmitting side 201 (e.g., ECU 101), but it can also be any storage device that can retain stored data even when the power supply is turned off, and can also be an external storage device or external server connected to the transmitting side 201.

[0033] <Example of transmission interval calculation> (i) Example using a map (table) A map (table) indicating the value of the transmission interval corresponding to the required response time is stored in advance in an internal storage device (SRAM 10111, FLASH memory 10112, or EEPROM 10113) of the transmitting side 201 (ECU 101). The transmitting side 201 can obtain the value of the transmission interval corresponding to the required response time calculated in S303 from the map and use it as the optimal transmission interval. Alternatively, a multiplication coefficient may simply be stored in the internal storage device. In this case, the transmission interval can be calculated by multiplying the multiplication coefficient by the calculated required response time.

[0034] (ii) Example using the average required response time and the average transmission interval The current transmission interval can be determined using the average required response time and the average transmission interval for each receiving device stored in the internal storage device of the sending side 201 or an external server device, etc. For example, the current transmission interval can be calculated according to the following formula (1).

[0035] This transmission interval IT p =(T p / T av )×IT av ··· (1)

[0036] Here, IT p is the transmission interval to be determined, T p is the required response time, T av is the average value of the past required response time of the receiving device, av indicates the average value of the past transmission intervals of the receiving device.

[0037] (iii) Example of transmission interval calculation FIG. 5 is a diagram showing the current required response time (required response time 203 from sending FirstFrame to receiving FlowControl) and the current transmission interval (transmission interval 204 during continuous data transmission) determined from the above formula (1).

[0038] For example, T p is 1.5ms, T av is 1.0ms, IT av If is 2ms, IT p is (1.5ms / 1.0ms) × 2.0ms = 3ms. Also, T p is 0.8ms, T av is 1.0ms, IT av If is 2ms, IT p is (0.8 ms / 1.0 ms) × 2.0 ms = 1.6 ms. In this way, it is possible to determine a transmission interval that takes into account the current communication load situation, using the transmission interval (average) under past communication load situations (average) as a reference.

[0039] <Regarding continuous transmission processing, including recalculation and storage of the average required response time and average transmission interval> FIG. 6 is a flowchart for explaining the continuous transmission process, which includes the process of FIG. 3 plus the process of recalculating and storing the average required response time and the average transmission interval.

[0040] (i) S301 to S306 The processing from S301 to S306 is as described in the explanation of FIG.

[0041] (ii) S601 The transmitting side 201 calculates the average required response time up to this point using the value of the current required response time calculated in S303, the average required response time up to the previous time (the previous time of continuous transmission), and the value of the number of continuous transmissions.The transmitting side 201 also calculates the average transmission interval up to this point using the value of the current transmission interval calculated in S304, the average transmission interval up to the previous time (the previous time of continuous transmission), and the value of the number of continuous transmissions.These values ​​are used when calculating the transmission interval for the next continuous transmission.

[0042] (iii) S602 The transmitting side 201 stores the average required response time and the average transmission interval obtained in S601 in a storage device (for example, the EEPROM 10113). When storing this information, as shown in Fig. 4, it is stored in an area in the storage device that is defined for each device (for example, the tool 102 or ECUs 103_1 to 103_n) of the receiving side 202 that is the communication target.

[0043] (iv) S307 The transmitting side 201 determines whether FlowControl has been received from the receiving side 202 within a predetermined time. If FlowControl has been received within the predetermined time (Yes in S307), the continuous transmission process ends. If FlowControl has not been received within the predetermined time (No in S307), the process returns to S301. In this case, the transmission interval is recalculated in S304 using the most recent average required response time and average transmission interval calculated in S601.

[0044] <Example of calculating the retry transmission interval> 7 is a diagram for explaining the concept of retrying continuous transmission processing. If the transmitting side 201 cannot receive FlowControl from the receiving side 202 even after continuous transmission has been performed at a transmission interval that has been determined once, the continuous transmission processing is retried. According to FIG. 6, if the answer is No in S307, steps S301 to S306 are executed again, but this is not limiting, and a new transmission interval can be calculated according to equation (2) by introducing a status coefficient and a failure experience coefficient. Transmission interval = previous transmission interval × status coefficient × failure experience coefficient (2)

[0045] (i) Condition coefficient selection rules After a continuous transmission process fails, the transmitting side 201 recalculates the time until it receives the FlowControl for the FirstFrame it retransmits to the receiving side 202, i.e., the required response time, and selects a different status coefficient depending on whether this is below the threshold. If it is below the threshold, the receiving side 202 is in a state where it can immediately retry after the continuous transmission failure; if it is not, it is in a state where it cannot immediately retry. Note that the threshold used here can be, for example, an estimate of the normal required response time from past communication history information (for example, an average value, an average value after excluding extreme values, etc.), and this information can be used as the threshold.

[0046] (i-1) If the required response time is below the threshold: If an immediate retry is possible In this case, the condition coefficient α can be set to a relatively low value (but not less than 1.0). For example, the condition coefficient α can be set to 1.2.

[0047] (i-2) When the required response time is greater than the threshold: When immediate retry after failure is not possible In this case, a value larger than the condition coefficient α is adopted as the condition coefficient β. For example, the condition coefficient β can be set to 1.5.

[0048] As described above, if a retry is not possible immediately after a continuous transmission process fails, it can be determined that the receiving capability of the receiving side 202 has decreased due to an increase in the processing load, and therefore the values ​​are set such that α<β.

[0049] (ii) Selection rule for failure experience coefficient γ The failure experience coefficient γ can be the number of consecutive failures. For example, γ=1 for the first failure, and γ=2 for the second consecutive failure. As described above, when transmission fails consecutively and retries are made, the transmission interval is set to be large for each retry.

[0050] (iii) Example of calculation of transmission interval during retry If the required response time of the receiving side 202 after the failure of the continuous transmission process is less than the threshold value, the transmission interval at the time of the first failure will be α=1.2 and γ=1, so from equation (2), it can be calculated as the previous transmission interval × status coefficient α(1.2) × failure experience coefficient γ(1) = previous transmission interval × 1.2.

[0051] Furthermore, if the required response time of the receiving side 202 after the successive transmission process fails is greater than the threshold, the transmission interval when three consecutive failures occur will be β=1.5 and γ=3, so from equation (2), it can be calculated as the previous transmission interval × status coefficient β(1.5) × failure experience coefficient γ(3) = previous transmission interval × 4.5.

[0052] <Modification> (i) Variation 1 8 is a diagram for explaining an overview of continuous transmission processing according to a modified example. In the above-described embodiment, an optimal transmission interval is set for each continuous transmission processing in accordance with the processing state (communication load, etc.) of the receiving side 202 based on the required response time of the receiving side 202, but the method of continuous transmission processing in accordance with the communication load of the receiving side 202 is not limited to this. For example, it is also possible to calculate and set an optimal number of transmission sizes (per transmission) in accordance with the processing state of the receiving side 202 during communication based on the required response time. In this case, a fixed value can be used as the transmission interval.

[0053] As shown in Figure 8, when the processing state of the receiving side 202 has room to spare, the transmission size per transmission is set large (for example, 64 bytes: see the left diagram of Figure 8), and when the load on the receiving side 202 is high, the transmission size per transmission is set small (for example, 8 bytes: see the right diagram of Figure 8).

[0054] For example, similar to the transmission interval, a map (table) specifying the transmission size corresponding to the required response time can be prepared in advance, and the transmission size corresponding to the currently detected required response time can be determined. Alternatively, the transmission size per transmission can be set to 64 bytes if the required response time is equal to or less than a predetermined threshold (e.g., 5 ms), and the transmission size per transmission can be set to 8 bytes if the required response time is greater than the predetermined threshold.

[0055] (ii) Modification 2 The initial continuous transmission process is performed at a transmission interval and a predetermined transmission size (transmission format) determined (calculated) based on the required response time (adaptive control of the transmission interval), but the continuous transmission process upon retry may be performed at a transmission size (determined by the method of the above-mentioned variant 1) determined (calculated) based on the transmission interval during the initial continuous transmission (when the continuous transmission failed) and a required response time calculated again (a required response time calculated separately from the initial continuous transmission). Alternatively, the reverse may be performed, that is, the initial continuous transmission process may be performed at a transmission size determined based on the required response time, and the transmission interval may be changed to perform the continuous transmission process upon retry.

[0056] <Summary> (i) According to this embodiment, the transmitting side 201 (transmitting side device) performs initial communication (First Frame transmission and Flow Control reception) with the receiving side 202 (receiving side device), confirms the response time (required response time) of the receiving side 202, and determines the mode (transmission interval and transmission size) of continuous transmission of data consisting of multiple frames to the receiving side 202 based on the response time. The transmitting side 201 then continuously transmits data to the receiving side 202 in units of frames according to the determined continuous transmission mode. This dramatically reduces the possibility of data loss compared to conventional techniques that determine a transmission interval (fixed value) before communication begins and transmits data continuously using this transmission interval regardless of the communication status. Furthermore, since the fixed transmission interval has a large margin to prevent data loss, it takes a relatively long time for the continuous transmission process to complete. On the other hand, according to this embodiment, the transmission interval and transmission size for continuous transmission are adaptively determined taking into account the current load status of the receiving side 202, so continuous transmission can be performed at an optimal transmission interval and transmission size. Therefore, continuous transmission can be completed in a shorter time than continuous transmission using a conventional fixed value. For example, if 1 Kbyte of data is transmitted in 8-byte increments per transmission (one frame), the number of transmissions is 1 Kbyte / 8 bytes = 12,500, and the number of transmission intervals is 12,500 - 1 = 12,499. In the conventional method, if the transmission interval is set to 2 ms including a margin (a fixed value regardless of the load status of the receiving side 202), the time required to complete continuous transmission is: Number of transmission intervals × Transmission interval = 12,499 × 2 ms = 24,998 ms = 24.9 s. On the other hand, according to this embodiment, if the transmission interval is calculated to be 1 ms based on the status of the receiving side 202, the time required to complete continuous transmission is: Number of transmission intervals × Transmission interval = 12,499 × 1 ms = 12,499 ms = 12.9 s, which is approximately half the time required in the conventional method.

[0057] (ii) The transmitting side 201 stores the response time information (value) and the determined continuous transmission mode information (transmission interval value or transmission size value) in at least one (either one or both) of its internal storage device (such as an EEPROM) or an external storage device (an external storage device or a server device), with separate storage areas for each receiving side 202 (see FIG. 4). Note that the internal storage device and the external storage device are preferably storage devices that can retain stored data even when the power supply to the transmitting side 201 is turned off. Furthermore, the storage in the storage area of ​​the storage device is performed each time the continuous transmission mode (transmission interval or transmission size) is determined. In this way, by accumulating information on the calculated continuous transmission mode, it can be used as a reference when determining the mode for subsequent continuous transmissions, making it possible to determine an appropriate mode.

[0058] (iii) The transmitting side 201 calculates the average required response time and the average transmission interval, and stores the average required response time and the average transmission interval (or transmission size) in separate storage areas for each device on the receiving side 202 in at least one of the internal storage device or the external storage device each time continuous transmission is completed. In this way, the current transmission interval and transmission size can be determined using the average required response time and the average transmission interval (or transmission size). Specifically, the current transmission interval can be calculated by dividing the current required response time by the average past required response time and multiplying the result by the average past transmission interval. Furthermore, the current transmission size, which is used instead of the transmission interval, can be calculated by dividing the current required response time by the average past required response time and multiplying the result by the average past transmission size.

[0059] (iv) In the in-vehicle communication system 100 according to this embodiment, a retry process is executed when a continuous transmission fails. With regard to the retry process, for example, after completing the current continuous transmission, the transmitting side 201 determines whether or not a reception completion response (FlowControl) indicating that reception of all data has been completed has been received from the receiving side 202, and if reception of the reception completion response has failed, the transmitting side 201 changes the transmission interval (extends the transmission interval) and retries the continuous transmission. When changing the transmission size, the failure of continuous transmission can be dealt with by reducing the previous transmission size.

[0060] The retry transmission interval can be calculated by multiplying a condition coefficient, which varies depending on whether the required response time (the time from sending the First Frame to receiving FlowControl) after failure to receive a reception completion response (FlowControl) is equal to or less than a predetermined threshold (for example, if it is equal to or less than the threshold, the condition coefficient is 1.2, and if it is greater than the threshold, the condition coefficient is 1.5), the number of consecutive failures to receive a reception completion response (FlowControl), and the previous transmission interval. This makes it possible to determine the next transmission interval taking into consideration the current load state of the receiving side 202 and the unique situation of consecutive failures. Regarding the transmission size, if the required response time after failure to receive a reception completion response (FlowControl) is equal to or less than a predetermined threshold, the condition coefficient is set to 0.8, and if it is greater than the threshold, the condition coefficient is set to 0.6. The previous transmission size may be multiplied by this condition coefficient and 1 / the number of consecutive failures to reduce the transmission size during a retry.

[0061] (v) The functions of the present embodiment and each example can also be realized by software program code. In this case, a storage medium on which the program code is recorded is provided to a system or device, and the computer (or CPU or MPU) of the system or device reads the program code stored on the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-mentioned embodiments, and the program code itself and the storage medium on which it is stored constitute the present disclosure. Examples of storage media for providing such program code include flexible disks, CD-ROMs, DVD-ROMs, hard disks, optical disks, magneto-optical disks, CD-Rs, magnetic tapes, non-volatile memory cards, and ROMs.

[0062] In addition, an operating system (OS) running on a computer may perform some or all of the actual processing based on instructions in the program code, and the functions of the above-described embodiments may be realized by this processing. Furthermore, after the program code is read from a storage medium and written to a memory on a computer, a CPU of the computer may perform some or all of the actual processing based on instructions in the program code, and the functions of the above-described embodiments may be realized by this processing.

[0063] Furthermore, the program code of the software that realizes the functions of the embodiments and each example may be distributed via a network and stored in a storage means such as a hard disk or memory of the system or device, or in a storage medium such as a CD-RW or CD-R, so that when in use, the computer (or CPU or MPU) of the system or device reads and executes the program code stored in the storage means or storage medium.

[0064] The processes and techniques described herein are not inherently related to any specific device and can be implemented by a combination of components. Various types of general-purpose devices can also be added. A dedicated device may be constructed to perform the functions of this embodiment and each example. Various functions can also be formed by appropriately combining multiple components disclosed in this embodiment and each example. For example, some components may be omitted from all the components shown in the embodiment and each example, or components from different examples may be appropriately combined.

[0065] Although specific embodiments are described in this disclosure, they are intended in all respects to be illustrative and not restrictive. Those skilled in the art will recognize that there are numerous combinations of hardware, software, and firmware suitable for implementing the disclosed technology. For example, the described software can be implemented in a wide variety of programming or scripting languages, such as assembler, C / C++, Perl, Shell, PHP, Java, etc.

[0066] Furthermore, in the above-described embodiment, the control lines and information lines are those that are considered necessary for the explanation, and not all control lines and information lines in the product are necessarily shown. All components may be interconnected.

[0067] In addition, other implementations of the present disclosure will be apparent to those skilled in the art from consideration of the present embodiments and examples. The specification and examples are exemplary only, with the scope and spirit of the technology of the present disclosure being indicated by the following claims. [Explanation of symbols]

[0068] 100 In-vehicle communication system 101 ECU (on-board control unit) 102 Tools (programming devices) 103_1 to 103_n ECUs 1011 Calculation device (microcomputer) 1012 Various ICs 1013 Communication equipment 10111, 10211 SRAM 10112, 10212 FLASH memory 10113, 10213 EEPROM 201 Sender 202 Receiver 203 Required response time (time required from sending data to receiving a response) 204 Transmission Interval

Claims

1. An in-vehicle communication system that continuously transmits data consisting of multiple frames from a transmitting device to a receiving device in a single communication, The sending device conducting an initial communication with the receiving device and verifying a response time by the receiving device; determining a form of continuous transmission of the data to the receiving device based on the response time; a process of continuously transmitting the data to the receiving device in units of frames according to the determined continuous transmission mode; Run the transmitting device determines, as the form of the continuous transmission, a transmission interval between frames in the continuous transmission based on the information on the response time; In-vehicle communication system.

2. In claim 1, An in-vehicle communication system, wherein the transmitting device confirms the response time in the initial communication by sending a message to the receiving device and receiving a response from the receiving device.

3. An in-vehicle communication system that continuously transmits data consisting of multiple frames from a transmitting device to a receiving device in a single communication, The sending device conducting an initial communication with the receiving device and verifying a response time by the receiving device; determining a form of continuous transmission of the data to the receiving device based on the response time; a process of continuously transmitting the data to the receiving device in units of frames according to the determined continuous transmission mode; Run an in-vehicle communication system, wherein the transmitting device performs a process of storing information on the response time and information on the determined continuous transmission form in at least one of an internal storage device provided inside the transmitting device or an external storage device provided outside the transmitting device, with separate storage areas for each receiving device.

4. In claim 3, The internal storage device and the external storage device are storage devices that can retain stored data even when the power supply is turned off.

5. In claim 3, an in-vehicle communication system, wherein the transmitting device stores information on the response time and information on the continuous transmission mode in the storage area for each receiving device every time the transmitting device determines the continuous transmission mode;

6. In claim 1, The transmitting device further executes a process of calculating an average value of the response time and an average value of the transmission interval.

7. In claim 6, The transmitting device further performs a process of storing information on the average response time and information on the average transmission interval each time the continuous transmission is completed, by separating storage areas for each receiving device in at least one of an internal storage device provided inside the transmitting device or an external storage device provided outside the transmitting device.

8. In claim 7, The transmitting device calculates the current transmission interval using the current response time, an average value of the past response times, and an average value of the past transmission intervals.

9. In claim 1, The sending device further comprises: a process of determining whether a reception completion response indicating completion of reception of all data has been received from the receiving device after the continuous transmission has been completed; a process of changing the transmission interval and retrying the continuous transmission when the reception of the reception completion response has failed; An in-vehicle communication system that performs the above.

10. In claim 9, The transmitting device extends the transmission interval and retries the continuous transmission.

11. In claim 10, the transmitting device changes the transmission interval and calculates the transmission interval when retrying the continuous transmission by multiplying a state coefficient that varies depending on whether the response time after failure to receive the reception completion response is equal to or less than a predetermined threshold, the number of consecutive failures to receive the reception completion response, and the previous transmission interval.

12. In claim 11, An in-vehicle communication system, wherein the condition coefficient is 1.0 or greater, and the condition coefficient when the response time is equal to or less than the predetermined threshold is smaller than the condition coefficient when the response time is greater than the predetermined threshold.

13. In claim 1, The transmitting device determines a transmission size of the data in the continuous transmission based on the response time information as the form of the continuous transmission.

14. 1. An in-vehicle communication method for continuously transmitting data made up of a plurality of frames in a single communication from a transmitting device in a vehicle to a receiving device in the vehicle, comprising: The sending device performs an initial communication with the receiving device and sends a message to the receiving device; the receiving device returning a response to the sending device approving the contents of the message; the sending device calculating a response time, which is the time from sending the message to receiving the response; the transmitting device determining a form of continuous transmission of the data to the receiving device based on the response time; the transmitting device continuously transmitting the data to the receiving device in units of frames in accordance with the determined continuous transmission format; Including, the transmitting device determines, as the form of the continuous transmission, a transmission interval between frames in the continuous transmission based on the information on the response time; In-vehicle communication methods.

Images