Vehicle-mounted communication system and vehicle-mounted communication method

Abstract

Provided is an in-vehicle communication system that continuously transmits data comprising a plurality of frames from a transmission-side device to a reception-side device by one-time communication so as to be able to reduce the occurrence of data overflow at the reception side, in which the transmission-side device performs a process of performing initial communication with the reception-side device, and performing a process of performing secondary communication with the reception-side device; processing for confirming the response time of the receiving-side device; a process for determining a manner in which data is continuously transmitted to the reception-side device on the basis of the response time; and a process for continuously transmitting data to the reception-side device in units of frames in accordance with the determined continuous transmission mode (referring to Figure 2).

Description

Technical Field

[0001] The invention relates to a vehicle-mounted communication system and a vehicle-mounted communication method. Background Art

[0002] In a vehicle-mounted control system, for example, in a reprogramming process, a reprogramming tool (program writing device) is used to continuously send data to an ECU (Electronic Control Unit: a vehicle-mounted control unit). In recent years, in order to enhance security, large amounts of data are increasingly being sent not only from the tool but also from the ECU to the tool or other ECUs (continuously in frames).

[0003] For example, non-patent document 1 stipulates that before communication between the transmitting side and the receiving side is established, the transmission interval when continuously transmitting data is predetermined to an arbitrary fixed value according to the model of the receiving side device, and continuous transmission processing is performed at the fixed transmission interval. Prior art literature Non-patent literature

[0004] Non-patent document 1: ISO 15765-2Third 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 that the invention aims to solve

[0005] However, if continuous transmission processing is performed at a fixed transmission interval determined before the start of communication as in the technology specified in ISO15765-2, when the processing load on the receiving-side device increases, the reception processing may not be able to keep up, and the transmitted data may overflow. In view of this situation, the present invention proposes a technology that can reduce the occurrence of data overflow on the receiving side. Technical means of solving problems

[0006] In order to solve the above-mentioned problems, as an example, the present invention discloses a vehicle-mounted communication system, which continuously sends data consisting of multiple frames from a sending side device to a receiving side device through a single communication, wherein the sending side device performs the following processing: initial communication with the receiving side device, and confirming the response time of the receiving side device; determining a method for continuously sending data to the receiving side device based on the response time; and continuously sending data to the receiving side device in units of frames according to the determined continuous sending method.

[0007] Other features related to the present invention are apparent from the description and drawings of this specification. In addition, the present invention is achieved and realized by means of elements and combinations of various elements as well as the following detailed description and the appended claims. The description in this specification is merely exemplary and is not intended to limit the claims or application examples of the present invention in any sense. Effects of the Invention

[0008] According to the technology of the present invention, the occurrence of data overflow on the receiving side can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a diagram showing a schematic configuration example of the vehicle-mounted communication system 100 according to the present embodiment. Figure 2 This is a diagram for explaining an overview of determining a transmission interval when continuously transmitting data according to the present embodiment. Figure 3 This is a flowchart for explaining the details of the continuous transmission process of this embodiment. Figure 4 This is a diagram showing an example of how each parameter is stored in a storage device (for example, EEPROM 10113) on the transmission side 201. Figure 5 This is a diagram showing the required response time this time (the required response time 203 from FirstFrame transmission to FlowControl reception) and the transmission interval this time (the transmission interval 204 when data is continuously transmitted) determined by the above formula (1). Figure 6 It is used to illustrate Figure 3 The processing includes a flowchart of continuous transmission processing of recalculating the average value of the required response time and the average value of the transmission interval and storing the processing. Figure 7 This is a diagram for explaining the concept of retry in the continuous transmission process. Figure 8 It is a diagram for explaining an overview of continuous transmission processing according to a modified example. DETAILED DESCRIPTION

[0010] The embodiment of the present invention discloses that in a vehicle-mounted system, during a communication operation between a transmitting side and a receiving side, the transmitting side adaptively determines a continuous transmission method consisting of a transmission interval and a transmission size used to continuously transmit data to the receiving side, and based on this, performs continuous transmission of multiple frames (of a specified size) of data. Thus, overflow of data on the receiving side can be prevented.

[0011] Hereinafter, the embodiments and examples of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, functionally identical elements are sometimes represented by the same reference numerals. In addition, although the accompanying drawings show specific embodiments and installation examples based on the principles of the present invention, these are for understanding the present invention and are by no means intended to limit the present invention.

[0012] In the present embodiment, those skilled in the art have described in full detail for implementing the present invention, but other installations and modes may be performed, and it is necessary to understand that changes in the configuration and structure and replacement of various elements may be performed without departing from the scope and spirit of the technical idea of ​​the present invention. Therefore, the following description cannot be limited to this for interpretation.

[0013] <Configuration Example of In-Vehicle Communication System> Figure 1 1 is a diagram showing a schematic configuration example of the vehicle-mounted communication system 100 according to the present embodiment. Figure 1 In the vehicle communication system 100, only the part related to the technology of the present invention is extracted to be constructed, but it may also include Figure 1 Elements other than those shown.

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

[0015] ECU101 includes a computing device (microcomputer: microcomputer) 1011, various ICs 1012, and a communication device 1013. The computing device 1011 includes, for example, at least one of SRAM 10111, flash memory 10112, and EEPROM 10113 as an internal storage device. In addition, SRAM 10111, flash memory, and EEPROM 10113 may also be provided outside the computing device 1011. In addition, ECU101 may also be communicatively connected to, for example, a server device (not shown) or an external storage device (not shown).

[0016] The tool 102 includes a computing device 1021, various ICs 1022, and a communication device 1023 as internal components, similarly to the ECU 101. The computing device 1021 includes, for example, at least one of an SRAM 10211, a flash memory 10212, or an EEPROM 10213 as an internal storage device. In addition, similarly to the ECU 101, the tool 102 may be connected to a server device (not shown) or an external storage device (not shown) in a communicable manner. The other plurality of ECUs 103_1 to 103_n different from the ECU 101 may also have the same internal configuration as that of the ECU 101 .

[0017] <Overview of determining the transmission interval> Figure 2 FIG. 1 is a diagram for explaining the outline of the transmission interval when determining continuous data transmission in the present embodiment. Figure 2 In the embodiment, the ECU 101 corresponds to a device on the transmission side 201 (transmission side device), and the tool 102 or any one of the ECUs 103_1 to 103_n corresponds to a device on the reception side 202 (reception side device).

[0018] In the case of continuous data transmission, a prior notification indicating continuous transmission is made from the transmission side 201 to the reception side 202. After receiving a permission notification (FlowControl described later: permission for continuous transmission) corresponding to the prior notification from the reception side 202, the transmission side 201 performs continuous transmission. The period from the prior notification to the reception is "the time required from data transmission to response reception (hereinafter referred to as "prior notification response time" or "required response time") 203". The prior notification is equivalent to the FirstFrame described later, but contains information on the specifications (method) of continuous transmission as the communication data content, for example, including: notification (signal) of the start of continuous transmission, information on the number of messages to be sent, and information on the transmission (communication) format (the amount of data in one transmission: for example, whether it includes transmission in 64-byte units or 8-byte units). For example, the transmission (communication) format can be a standard format and an extended format in CAN (Controller Area Network) communication.

[0019] When receiving ACK from the receiving side 202, the transmitting side 201 calculates (detects) the prior notice response time (required response time) 203, judges (estimates) the state of the receiving side 202 (processing load state) based on this, and calculates the "sending interval 204 when data is continuously sent". For example, if the prior notice response time 203 is longer than the prescribed time, it can be judged that the load on the receiving side 202 has increased, so the sending interval 204 can be set to be longer. The method of determining the sending interval 204 will be described in detail later. The transmission side 201 repeatedly transmits consecutive frames to the reception side 202 at the transmission interval 204 determined as described above.

[0020] As described above, the present embodiment is different from the prior art (for example, the above-mentioned ISO15765-2) (in the prior art, the sending interval is determined as a fixed value before the communication starts and cannot be changed afterwards). Since advance notification about continuous sending is made on the sending side 201 and the receiving side 202, and the sending interval 204 is adaptively determined based on the communication result, continuous sending can be performed taking into account the state of the receiving side 202, thereby maximizing the communication efficiency.

[0021] <Details of Continuous Transmission Processing> Figure 3 The main body of each step is the transmission side 201, that is, ECU101, but the technology of the present invention can also be the tool 102 as the transmission side device, so the following description will mark the main body of the action as the transmission side 201.

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

[0023] (ii)S302 The transmission side 201 waits until it receives FlowControl from the reception side 202. When FlowControl is received (YES in S302), the process proceeds to S303.

[0024] (iii)S303 The sending side 201 calculates the required response time (pre-notification response time 203) from the time when the FirstFrame (FF) is sent to the time when the FlowControl (FC) is received.

[0025] (iv)S304 The sending side 201 calculates the optimal sending interval 204 based on the prior notification response time 203 calculated in S303. Here, the so-called "optimal sending interval" at least refers to the sending interval (the time interval from sending a certain ConsecutiveFrame to sending the next ConsecutiveFrame) at which data overflow does not occur, and is usually a shorter time than in the past as long as the processing load of the receiving side 202 is not too large.

[0026] (v)S305 The transmission side 201 stores the required response time calculated in S303 and the transmission interval calculated in S304 in EEPROM 10113. The storage destination is not limited to EEPROM 10113, but may be SRAM 1011 or flash memory 10112, or an external server device or external storage device (not shown) via a network.

[0027] In the internal storage device (for example, EEPROM 10113) of the storage destination, a storage area may be divided for each device on the receiving side 202, and the value of the required response time and the value of the transmission interval (each time calculated) may be stored.

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

[0029] (vii)S307 After sending all the ConsecutiveFrames, the sending side 201 determines whether the FlowControl is received from the receiving side 202 within the specified time. If the FlowControl is received from the receiving side 202 within the specified time (if "Yes" in S307), the continuous sending process is completed. On the other hand, if the FlowControl is not received from the receiving side 202 within the specified time (if "No" in S307), it is determined that the executed continuous sending process has ended in failure, and the process is transferred (returned) to S301. When the continuous sending process ends in failure, the calculated value of the sending interval is inappropriate. Therefore, the process returns to S301 and the process of determining the sending interval is executed again.

[0030] <Saving Parameters to Storage Device> Figure 4 1 is a diagram showing an example of how each parameter is stored in a storage device (e.g., EEPROM 10113) of the transmission side 201. Here, each parameter may include, for example, a value of a required response time in each transmission and a value of a transmission interval in each continuous transmission. In addition, a required response time in the past (T av ) and the average of the past transmission intervals (IT av )’s average value.

[0031] like Figure 4As shown, the EEPROM 10113 for holding parameters has areas for storing the parameters of the tool 102 and ECUs 103_1 to 103_n, respectively. For example, for each of the reprogramming tool A401, the reprogramming tool B402, and the ECU 1_403, ..., areas X1 to Xn+2 are defined as areas for storing the values ​​of the required response time in the past in each device, and areas A1 to An+2 are defined as areas for storing the values ​​of the transmission interval in the past in each device. In this way, the EEPROM 10113 has areas X and A corresponding to the number of devices that the transmission side 201 may communicate with. Here, only the reprogramming tool is shown as a tool, but areas for other tools (for example, diagnostic tools) can also be set. In addition, the parameters can be managed by dividing the area according to the communication conditions (for example, the transmission (communication) format: one frame is composed of 64 bytes or 8 bytes) to each receiving side (the device of the communication counterpart).

[0032] As described above, the storage device may be an EEPROM 10113 inside the transmitting side 201 (eg, ECU 101), but may also be an external storage device or an external server connected to the transmitting side 201 as long as it is a storage device that can maintain stored data even when the power supply is disconnected.

[0033] <Example of calculating the transmission interval> (i) Example of using mapping (table) A mapping (table) indicating the value of the transmission interval corresponding to the required response time is stored in advance in the internal storage device (SRAM 10111, flash memory 10112 or EEPROM 10113) of the transmission side 201 (ECU 101). The transmission side 201 can obtain the value of the transmission interval corresponding to the required response time calculated in S303 based on the mapping and use it as the optimal transmission interval. Alternatively, it is also possible to store only the multiplication coefficient in the internal storage device. In this case, the transmission interval can be obtained by multiplying the calculated required response time by the multiplication coefficient.

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

[0035] This time's sending interval IT p＝ (T p / T av )×IT av …(1)

[0036] Here, IT p Indicates the sending interval that should be determined this time, T p Indicates the required response time for this time, T av It represents the average value of the required response time of the receiving device in the past. av Indicates the average value of the past transmission intervals of the receiving device.

[0037] (iii) Specific example of calculating the sending interval Figure 5 This is a diagram showing the required response time this time (the required response time 203 from FirstFrame transmission to FlowControl reception) and the transmission interval this time (the transmission interval 204 when data is continuously transmitted) determined by the above formula (1).

[0038] For example, in T p 1.5ms, T av 1.0ms, IT av When the IT p = (1.5ms / 1.0ms)×2.0ms=3ms. p 0.8ms, T av 1.0ms, IT av When the IT p (0.8 ms / 1.0 ms)×2.0 ms=1.6 ms. From this, it can be seen that the transmission interval (average) in the past communication load status (average) can be used as a reference to obtain the transmission interval that also takes the current communication load status into consideration.

[0039] <Regarding the continuous transmission process including the recalculation and storage of the average value of the required response time and the average value of the transmission interval> Figure 6 It is used to illustrate Figure 3 The processing includes a flowchart of continuous transmission processing of recalculating the average value of the required response time and the average value of the transmission interval and storing the processing.

[0040] (i) From S301 to S306 The processing from S301 to S306 is as in Figure 3 as described in the instructions.

[0041] (ii)S601 The sending side 201 uses the value of the required response time calculated in S303, the average value of the required response time up to the last time (the last continuous transmission), and the value of the number of continuous transmissions to calculate the average value of the required response time up to this time. In addition, the sending side 201 uses the value of the current transmission interval calculated in S304, the average value of the transmission interval up to the last time (the last continuous transmission), and the value of the number of continuous transmissions to calculate the average value of the transmission interval up to this time. These values ​​are used when calculating the transmission interval for the next continuous transmission.

[0042] (iii)S602 The sending side 201 stores the average value of the required response time and the average value of the sending interval obtained in S601 in a storage device (e.g., EEPROM 10113). Figure 4 As shown, the data is stored in an area in a storage device that is determined for each device (eg, tool 102 or ECUs 103_1 to 103_n) on the receiving side 202 of the communication object.

[0043] (iv)S307 The sending side 201 determines whether the FlowControl is received from the receiving side 202 within the specified time. If the FlowControl is received within the specified time (if "Yes" in S307), the continuous sending process ends. If the FlowControl is not received within the specified time (if "No" in S307), the process transfers to S301. In this case, the sending interval is calculated again in S304, and the sending interval is calculated again using the average value of the latest required response time calculated in S601 and the average value of the sending interval.

[0044] <Example of calculating the transmission interval during retry> Figure 7 2 is a diagram for explaining the concept of retrying the continuous transmission process. When the transmission side 201 cannot receive FlowControl from the reception side 202 even if continuous transmission is performed at a temporarily determined transmission interval, the continuous transmission process is retried. Figure 6 , from S301 in the case of "No" in S307, S306 is executed again, but it is not limited to this. The state coefficient and failure experience coefficient can be introduced to calculate the new sending interval according to formula (2). Sending interval = last sending interval × status coefficient × failure experience coefficient…(2)

[0045] (i) Selection rules of state coefficients After the continuous transmission process fails, the transmission side 201 recalculates the time until receiving the FlowControl corresponding to the FirstFrame sent again to the receiving side 202, that is, the required response time, and selects different state coefficients depending on whether it is below the threshold. If it is below the threshold, the receiving side 202 is in a state where it can retry immediately after the continuous transmission fails, otherwise it becomes a state where it cannot retry immediately. In addition, for example, the threshold used here can estimate the usual required response time (for example, average value, average value after removing extreme values, etc.) based on past communication history information, so this information can be used as a threshold.

[0046] (i-1) When the required response time is below the threshold: when retry is possible immediately In this case, a relatively low value (however, 1.0 or more) may be adopted as the state coefficient α. For example, the state coefficient α may be 1.2.

[0047] (i-2) The required response time is greater than the threshold: the situation where retry is not possible immediately after failure At this time, as the state coefficient β, a value larger than the state coefficient α is adopted. For example, the state coefficient β may be 1.5.

[0048] As described above, when the continuous transmission process cannot be retried immediately after failure, it can be determined that the reception capability of the receiving side 202 has decreased due to the increase in the processing load, so the value is set in the relationship of α<β.

[0049] (ii) Selection rules for failure experience coefficient γ As the failure experience coefficient γ, the number of consecutive failures can be used. For example, γ=1 at the first failure and γ=2 at the second consecutive failure. As described above, when retrying after continuous transmission failures, the transmission interval is set larger for each retry.

[0050] (iii) Example of calculating the transmission interval during retry Since the required response time of the receiving side 202 after the continuous sending processing fails is below the above threshold, the sending interval at the time of the first failure is α=1.2 and γ=1, so it can be calculated according to formula (2) through the last sending interval×state coefficient α(1.2)×failure experience coefficient γ(1)=last sending interval×1.2.

[0051] In addition, the required response time of the receiving side 202 after continuous transmission processing failures is greater than the threshold, and the transmission intervals for three consecutive failures are β=1.5 and γ=3. Therefore, it can be calculated according to formula (2) by the last transmission interval × state coefficient β(1.5) × failure experience coefficient γ(3) = last transmission interval × 4.5.

[0052] <Modification> (i) Modification 1 Figure 8 2 is a diagram for explaining the outline of the continuous transmission process of the modified example. In the above embodiment, according to the required response time of the receiving side 202, the optimal transmission interval is set for each continuous transmission process according to the processing state (communication load, etc.) of the receiving side 202, but the method of the continuous transmission process corresponding to the communication load of the receiving side 202 is not limited to this. For example, the optimal transmission size (per 1 transmission) corresponding to the processing state of the receiving side 202 during communication can also be calculated and set according to the required response time. In this case, the transmission interval can adopt a fixed value.

[0053] like Figure 8 As shown, when the processing state of the receiving side 202 has a margin, the transmission size per transmission is set to be larger (for example, 64 bytes: see Figure 8 Left figure), when the load on the receiving side 202 is high, the transmission size of each transmission is set to be small (for example, 8 bytes: see Figure 8 right).

[0054] For example, similar to the transmission interval, a mapping (table) that specifies the transmission size corresponding to the required response time can be prepared in advance to determine the transmission size corresponding to the required response time detected this time. Alternatively, when the required response time is less than a specified threshold (e.g., 5ms), the transmission size of each transmission is set to 64 bytes, and when the required response time is greater than the specified threshold, the transmission size of each transmission is set to 8 bytes.

[0055] (ii) Modification 2 The initial continuous transmission process is performed with a transmission interval determined (calculated) based on the required response time and a predetermined transmission size (transmission format) (adaptive control of the transmission interval), but the continuous transmission process during the retry may be performed with a transmission size determined (calculated) based on the transmission interval during the initial continuous transmission (when the continuous transmission fails) and the required response time calculated (detected) again (the required response time calculated separately from the initial continuous transmission) (determined by the method of the above-mentioned modification 1). In addition, the opposite may be performed, that is, the initial continuous transmission process may be performed with a transmission size determined according to the required response time, and the continuous transmission process during the retry may be performed by changing the transmission interval.

[0056] <Conclusion> (i) According to the present embodiment, the sending side 201 (sending side device) and the receiving side 202 (receiving side device) perform initial communication (FirstFrame transmission and FlowControl reception), confirm the response time (required response time) of the receiving side 202, and determine the method (transmission interval and transmission size) of continuously transmitting data consisting of multiple frames to the receiving side 202 based on the response time. Then, the sending side 201 continuously transmits data to the receiving side 202 in units of frames according to the determined continuous transmission method. As a result, the possibility of data overflow can be significantly reduced compared to the prior art in which a transmission interval (fixed value) is determined before the start of communication and the transmission interval is used for continuous transmission regardless of the communication status. In addition, the fixed value transmission interval takes a large margin to avoid overflow, so it takes a relatively long time until the continuous transmission process is completed. On the other hand, according to the present embodiment, since the transmission interval and transmission size in continuous transmission are adaptively determined in consideration of the current load status of the receiving side 202, continuous transmission can be performed with the optimal transmission interval and transmission size. Therefore, continuous transmission can be completed in a shorter time than the conventional continuous transmission using a fixed value. For example, when 1K bytes of data are transmitted with 8 bytes per transmission (1 frame), the number of transmissions is 1K bytes / 8 bytes = 12500 times, and the number of transmission intervals is 12500-1 = 12499 times. In the conventional method, when the transmission interval includes a margin and is set to 2 ms (a fixed value that is independent of the load condition of the receiving side 202), the time required to complete continuous transmission = the number of transmission intervals × the transmission interval = 12499 times × 2 ms = 24998 ms = 24.9 s. On the other hand, according to the present embodiment, when the transmission interval is calculated to be 1 ms based on the state of the receiving side 202, the time required to complete continuous transmission = the number of transmission intervals × the transmission interval = 12499 times × 1 ms = 12499 ms = 12.9 s, which can be shortened to about half of the conventional method.

[0057] (ii) The transmission side 201 divides the storage area for each reception side 202 in at least one (either one or both) of its internal storage device (EEPROM, etc.) or external storage device (external storage device or server device) (see Figure 4), and saves the information (value) of the response time and the information of the determined continuous transmission method (the value of the transmission interval or the value of the transmission size). In addition, the internal storage device and the external storage device are preferably storage devices that can maintain the stored data even if the power supply of the transmission side 201 is disconnected. In addition, each time the continuous transmission method (transmission interval or transmission size) is determined, it is saved to the storage area of ​​the storage device. In this way, by storing the information of the calculated continuous transmission method, it can be used as a reference when determining the method of continuous transmission to be executed later, and an appropriate method can be determined.

[0058] (iii) The sending side 201 calculates the average value of the required response time and the average value of the sending interval, and in at least one of the above-mentioned internal storage device or external storage device, a storage area is separated for each device of the receiving side 202, and the average value of the required response time and the average value of the sending interval (or the sending size) are saved each time continuous sending is completed. In this way, the average value of the required response time and the average value of the sending interval (or the sending size) can be used to determine the current sending interval and the sending size. Specifically, the current sending interval can be calculated by dividing the current required response time by the average value of the required response time in the past and multiplying the result by the average value of the sending interval in the past. In addition, the current sending size used instead of the sending interval can be calculated by dividing the current required response time by the average value of the required response time in the past and multiplying the result by the average value of the sending size in the past.

[0059] (iv) In the vehicle communication system 100 of the present embodiment, a retry process is performed when continuous transmission fails. Regarding the retry process, for example, after completing the current continuous transmission, the transmission side 201 determines whether a reception completion response (FlowControl) indicating that the reception of all data has been completed is received from the reception side 202. When the reception completion response fails, the transmission interval is changed (the transmission interval is extended) to retry the continuous transmission. In the case of changing the transmission size, continuous transmission failure can be dealt with by reducing the previous transmission size.

[0060] The sending interval at the time of retry can be calculated by multiplying a state coefficient (for example, if it is below the threshold, the state coefficient = 1.2, if it is greater than the threshold, the state coefficient = 1.5) that varies depending on whether the required response time after the reception failure of the reception completion response (FlowControl) (the time from the FirstFrame being sent to the reception of the FlowControl) is below a specified threshold, the number of consecutive failures in receiving the reception completion response (FlowControl), and the last sending interval. In this way, the next sending interval can be determined in consideration of the current load state of the receiving side 202 and special conditions such as consecutive failures. In addition, regarding the sending size, if the required response time after the reception failure of the reception completion response (FlowControl) is below the specified threshold, the state coefficient = 0.8, and if it is greater than the threshold, the state coefficient = 0.6, and the sending size at the time of retry can be reduced by multiplying it by the inverse of the number of consecutive failures by the last sending size.

[0061] (v) The functions of the present embodiment and each embodiment can also be implemented by the program code of the software. In this case, a storage medium recording the program code is provided to a system or device, and the computer (or CPU or MPU) of the system or device reads out the program code stored in the storage medium. In this case, the program code read out from the storage medium itself implements the functions of the above-mentioned embodiments, and the program code itself and the storage medium storing the program code constitute the present invention. As a storage medium for providing such a program code, for example, a floppy disk, a CD-ROM, a DVD-ROM, a hard disk, an optical disk, a magneto-optical disk, a CD-R, a magnetic tape, a non-volatile memory card, a ROM, etc. are used.

[0062] In addition, according to the instructions of the program code, the OS (operating system) running on the computer may perform part or all of the actual processing, and the functions of the above-mentioned embodiments may be realized through this processing. Furthermore, after the program code read from the storage medium is written into the memory on the computer, according to the instructions of the program code, the CPU of the computer may perform part or all of the actual processing, and the functions of the above-mentioned embodiments may be realized through this processing.

[0063] Furthermore, the program code of the software that implements the functions of the implementation methods and each embodiment can also be distributed through the network and stored in a storage unit such as a hard disk or memory of the system or device or a storage medium such as CD-RW, CD-R, etc. When in use, the computer (or CPU or MPU) of the system or device reads and executes the program code stored in the storage unit or the storage medium.

[0064] The processes and techniques described herein do not essentially involve any specific device and can be implemented by a combination of components. In addition, various types of equipment for general purposes can also be added. In order to perform the functions of this embodiment and each embodiment, a dedicated device can also be constructed. In addition, various functions can also be formed by appropriately combining multiple constituent elements disclosed in this embodiment and each embodiment. For example, several constituent elements can be deleted from all the constituent elements shown in the embodiment and each embodiment, and the constituent elements of different embodiments can also be appropriately combined.

[0065] Although specific embodiments are described in the present invention, these embodiments are not intended to be limiting in all respects, but rather to be illustrative (to understand the technology of the present invention). It will be appreciated by those of ordinary skill in the art that there are many combinations of hardware, software, and firmware suitable for implementing the technology of the present invention. For example, the software described may be implemented in a variety of programming or scripting languages, such as assembler, C / C++, perl, Shell, PHP, Java (registered trademark), etc.

[0066] Furthermore, in the above-mentioned embodiments, the control lines and information lines are those that are considered necessary for the purpose of explanation, and not all the control lines and information lines are necessarily shown in the product. All the components may be connected to each other.

[0067] In addition, those skilled in the art can understand other implementations of the present invention through discussions of this embodiment and various examples. The description and specific examples are merely exemplary, and the technical scope and spirit of the present invention are given in the subsequent claims. Explanation of symbols

[0068] 100 In-vehicle communication systems 101ECU (vehicle control unit) 102 tool (program writing device) 103_1~103_n ECU 1011 computing device (microcomputer: microcomputer) 1012 Various ICs 1013 communication device 10111, 10211 SRAM 10112, 10212 flash memory 10113, 10213 EEPROM 201 Sending side 202 receiving side 203 Response time required (the time required from data sending to response receiving) 204 Sending interval.

Claims

1. An in-vehicle communication system for continuously transmitting data consisting of a plurality of frames from a transmitting device to a receiving device in one communication, wherein: The sending side device performs the following processing: Performing initial communication with the receiving device to confirm the response time of the receiving device; Determining, based on the response time, a method of continuously sending the data to the receiving device; and The process of continuously sending the data to the receiving device in frames according to the determined continuous sending method.

2. The vehicle-mounted communication system according to claim 1, characterized in that: The transmitting-side device determines, based on the information of the response time, a data transmission interval of each frame unit in the continuous transmission as the method of the continuous transmission.

3. The vehicle-mounted communication system according to claim 1, characterized in that: The transmitting device confirms the response time by transmitting a message to the receiving device and receiving a response from the receiving device in the initial communication.

4. The vehicle-mounted communication system according to claim 1, characterized in that: The sending side device divides the storage area according to the receiving side device in at least one of an internal storage device provided inside the sending side device or an external storage device provided outside the sending side device, and performs processing to save the information of the response time and the information of the determined continuous sending method.

5. The vehicle-mounted communication system according to claim 4, characterized in that: The internal storage device and the external storage device are storage devices capable of retaining stored data even when power supply is turned off.

6. The vehicle-mounted communication system according to claim 4, characterized in that: The transmission-side device stores the information of the response time and the information of the continuous transmission method in the storage area of ​​each of the reception-side devices every time the continuous transmission method is determined.

7. The vehicle-mounted communication system according to claim 2, characterized in that: The transmission-side device further performs a process of calculating an average value of the response time and an average value of the data transmission interval.

8. The vehicle-mounted communication system according to claim 7, characterized in that: The sending side device further distinguishes the storage area according to the receiving side device in at least one of an internal storage device arranged inside the sending side device or an external storage device arranged outside the sending side device, and performs processing to save the information of the average value of the response time and the average value of the data sending interval each time the continuous sending is completed.

9. The vehicle-mounted communication system according to claim 8, characterized in that: The transmission-side device calculates the data transmission interval for this time by using the response time for this time, the average value of the response times in the past, and the average value of the data transmission intervals in the past.

10. The vehicle-mounted communication system according to claim 2, characterized in that: The sending side device also performs the following processing: After the continuous transmission is completed, a process of determining whether a reception completion response indicating that reception of all data is completed is received from the receiving-side device; and When reception of the reception completion response fails, the data transmission interval is changed to retry the continuous transmission process.

11. The vehicle-mounted communication system according to claim 10, characterized in that: The transmitting-side device extends the data transmission interval to retry the continuous transmission.

12. The vehicle-mounted communication system according to claim 11, characterized in that: The sending side device changes the data sending interval by multiplying the state coefficient that varies depending on whether the response time after the failure to receive the reception completion response is below a specified threshold, the number of consecutive failures in receiving the reception completion response, and the last data sending interval, and calculates the data sending interval during the retry of the continuous sending.

13. The vehicle-mounted communication system according to claim 12, characterized in that: The state coefficient is greater than or equal to 1.0, and the state coefficient when the response time is less than or equal to the predetermined threshold value is smaller than the state coefficient when the response time is greater than the predetermined threshold value.

14. The vehicle-mounted communication system according to claim 1, characterized in that: The sending side device determines the data transmission size of each frame unit in the continuous transmission according to the information of the response time as the method of the continuous transmission.

15. A vehicle-mounted communication method, wherein data consisting of a plurality of frames is continuously transmitted from a transmitting device in a vehicle to a receiving device in the vehicle through one communication, wherein: The sending device performs initial communication with the receiving device and sends a message to the receiving device. The receiving device returns a response acknowledging the content of the message to the sending device, The sending device calculates the time from the sending of the message to the receiving of the response, that is, the response time, The sending device determines a method of continuously sending the data to the receiving device based on the response time, The sending side device continuously sends the data to the receiving side device in frames according to the determined continuous sending method.

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