Network system and communication method for a network system

Abstract

The invention relates to a network system comprising: - at least one synchronous bus system to which at least one first network component is connected, the at least one synchronous bus system being configured for a task-synchronous operation according to a bus schedule; - at least one asynchronous bus system to which at least one second network component is connected; and - a gateway which is connected to the at least one synchronous bus system and to the at least one asynchronous bus system and is configured to provide a time base for the at least one asynchronous bus system in order to synchronize tasks on the basis of the bus schedule such that the at least one asynchronous bus system is likewise configured for a task-synchronous operation using the time base.

Description

[0001] 24-1264

[0002] Network system and communication methods for a network system

[0003] The present disclosure relates to a network system, a vehicle with such a network system, a communication method for a network system, and a storage medium for executing the communication method. The present disclosure relates in particular to task synchronization on heterogeneous bus systems.

[0004] State of the art

[0005] FlexRay is a serial, deterministic, and fault-tolerant communication protocol specifically designed for use in automobiles. It was conceived to meet the increasing demands for high data rates, real-time capability, and reliability in modern vehicles. Deterministic communication means that data is transmitted across a network at predetermined and guaranteed times—in so-called time slots—but this does not necessarily imply that the system behavior (e.g., end-to-end latency) is also deterministic.

[0006] Time Division Multiple Access (TDMA) is typically used as the access method. This results in undeterministic system behavior because tasks and the TDMA scheme (bus schedule) generally drift relative to each other. To ensure fully deterministic system behavior, data, and especially the tasks that provide this data, must be time-aligned with the bus schedule. This ensures that the data is available for transmission within a constant time relative to a designated time slot and is processed within a constant time relative to this time slot on the receiving side. This method can generally be described as task-synchronous operation on a synchronous bus. The execution time of the tasks and the bus schedule are synchronized, with the bus itself providing the common time base against which the tasks are aligned.Are individual (or all) tasks based on a 24-1264?

[0007] By aligning with excellent time slots, the data belonging to these tasks is always processed deterministically.

[0008] Task-synchronous operation and deterministic system behavior can also be achieved on asynchronous buses such as CAN or Ethernet. This requires that the transmission latency can be limited to a maximum value. This requirement can generally be met through Quality of Service (QoS) measures. If a common time base is distributed across the asynchronous system and tasks are aligned with this time base to maintain the maximum latency between data provision and processing, the delay between data generation and processing remains constant, and the system is therefore completely deterministic.

[0009] Currently, there are efforts to gradually phase out the FlexRay bus (or time-controlled / synchronous buses in general) in vehicles due to inefficient resource utilization and high system design complexity. However, no technical concept yet exists that enables adequate, system-wide task synchronization between tasks running on a TDMA-based / synchronous bus system like FlexRay and tasks running on an asynchronous bus system like CAN. Therefore, a smooth migration from synchronous to asynchronous buses is currently not possible without compromising deterministic system behavior.

[0010] Disclosure of the invention

[0011] It is an objective of the present disclosure to specify a network system, a vehicle with such a network system, a communication method for a network system, and a storage medium for executing the communication method, which enable task synchronization on heterogeneous bus systems. In particular, it is an objective of the present disclosure to enable efficient and deterministic data exchange across heterogeneous bus systems. 24-1264

[0012] This problem is solved by the subject matter of the independent claims. Advantageous embodiments are specified in the dependent claims.

[0013] According to an independent aspect of the present disclosure, a network system, particularly for a motor vehicle, is specified. The network system comprises:

[0014] at least one synchronous bus system to which at least one first network component is connected, wherein the at least one synchronous bus system is set up for task-synchronous operation according to a bus schedule;

[0015] at least one asynchronous bus system to which at least one second network component is connected; and

[0016] a gateway that is connected to the at least one synchronous bus system and the at least one asynchronous bus system and is configured to provide a time base for the at least one asynchronous bus system for task synchronization based on the bus schedule, such that the at least one asynchronous bus system is also configured for task-synchronous operation using the time base.

[0017] This allows the synchronous bus system to determine when tasks are executed within the synchronous system and simultaneously define a clock for the time base according to which the connected network components in the asynchronous system execute their tasks. If all network components connected to this synchronous bus system synchronize their tasks according to the predefined bus schedule (or time slot) and latency is factored in via the gateway, deterministic and coordinated task execution within the heterogeneous overall system can be ensured.

[0018] The gateway, which is connected to both the synchronous and asynchronous bus systems, generates a synchronized time base based on the bus schedule. This time reference serves as an orientation for the network components on the asynchronous bus system, allowing them to synchronize with the clock signal provided by the synchronous bus system. The time base enables the network components on the asynchronous 24-1264 bus system to...

[0019] The bus system, in particular, is able to calculate a beginning and an end of any time slots and to align its (asynchronous) tasks accordingly.

[0020] The network components connected to the asynchronous bus system use this derived time base to synchronize and time their own tasks accordingly. This ensures that even in a hybrid network with synchronous and asynchronous bus systems, uniform temporal orchestration of tasks and, consequently, deterministic system behavior is possible.

[0021] A synchronous bus system is a time-controlled communication system in which data exchange occurs according to a predefined and fixed schedule. All network participants are synchronized and send and receive data at precisely defined times within a recurring time frame. This enables deterministic communication, as the delay and sequence of data transmission are exactly predictable. If, at the same time, the execution times of individual or all tasks are aligned with the predefined and fixed schedule, a fully deterministic or synchronous (sub)system results.

[0022] An asynchronous bus system is an event-driven communication system in which data exchange does not occur according to a fixed schedule, but rather on demand. Network components send messages as soon as they have new data and process or receive it according to its priority and availability. This means that transmission time is not guaranteed, which can lead to delays, especially in heavily loaded networks. However, if the execution times of individual or all tasks are synchronized and orchestrated, a fully deterministic (asynchronous) (sub)system results.

[0023] Preferably, the at least one first network component and / or the at least one second network component are selected from the group comprising, or consisting of, electronic control units (ECUs), sensors, and actuators. An electronic control unit (ECU, Electronic24-1264)

[0024] The Control Unit (CCU) is an electronic unit responsible for processing sensor data and controlling actuators.

[0025] Preferably, the at least one synchronous bus system comprises or is a FlexRay bus system. The FlexRay bus system is a synchronous, deterministic, and fault-tolerant communication protocol specifically designed for use in safety-critical applications in the automotive industry. It enables highly reliable, time-controlled, and fast data transmission between different electronic control units (ECUs).

[0026] Preferably, the at least one asynchronous bus system comprises or is a CAN bus system. The CAN bus system (Controller Area Network) is an asynchronous, event-driven, and fault-tolerant communication protocol specifically designed for networking electronic control units (ECUs) in vehicles. It enables serial, priority-based communication, allowing multiple ECUs to exchange data without central control. However, the present disclosure is not limited to this, and the at least one asynchronous bus system could, for example, also be an Ethernet system.

[0027] Preferably, the bus schedule is a Time Division Multiple Access (TDMA) schedule. A TDMA schedule is based on a time-controlled transmission method in which bus communication takes place within a common frequency band, but at different times.

[0028] Preferably, the at least one asynchronous bus system exhibits completely deterministic system behavior in task-synchronous operation.

[0029] Preferably, the gateway is configured to generate the time base by continuously deriving a time interval between its own local time and a last relevant timing event (such as the start of the next cycle or the beginning of any other distinguished slot) from at least one 24-1264

[0030] synchronous bus system determined and any offset corrected by adjusting the local time; and the adjusted local time distributed as the time basis for synchronizing the tasks on the at least one asynchronous bus system.

[0031] Preferably, the gateway is configured to adjust the local time so that at the start time of the next cycle it is a multiple of the cycle time itself.

[0032] Preferably, the gateway is configured to generate a time tuple comprising the local time and the correspondingly derived time base used for task synchronization of the at least one asynchronous bus system.

[0033] According to another independent aspect of the present disclosure, a vehicle, in particular a motor vehicle, is specified. The vehicle comprises the network system according to the embodiments of the present disclosure.

[0034] The term "vehicle" includes cars, trucks, vans, buses, motorhomes, motorcycles, etc., used for the transport of people, goods, etc. In particular, the term includes motor vehicles for passenger transport.

[0035] According to another independent aspect of the present disclosure, a communication method for a network system, in particular a motor vehicle, is specified. The communication method comprises:

[0036] Determine, through a gateway connected to at least one synchronous bus system and at least one asynchronous bus system, a time base for the at least one asynchronous bus system for task synchronization, which is based on or derived from a bus schedule of the at least one synchronous bus system; and

[0037] Execution of tasks by at least one network component connected to the at least one asynchronous bus system, based on the time base provided by the gateway, which is derived from the bus schedule of the synchronous bus. 24-1264

[0038] The communication procedure can implement the aspects of the network system described in this document.

[0039] According to another independent aspect of the present disclosure, a software (SW) program is specified. The SW program can be configured to run on one or more processors and thereby execute the communication method for a network system described in this document.

[0040] According to another independent aspect of the present disclosure, a storage medium is specified. The storage medium may include a software program configured to run on one or more processors and thereby execute the communication method for a network system described in this document.

[0041] According to another independent aspect of the present disclosure, software with program code is specified. The software is designed to carry out the communication procedure for a network system when the software runs on one or more software-controlled devices.

[0042] According to another independent aspect of the present disclosure, a system is specified. The system comprises one or more processors; and at least one memory connected to the one or more processors and containing instructions that can be executed by the one or more processors to perform the communication method for a network system described in this document.

[0043] A processor or processor module is a programmable computing unit, i.e., a machine or an electronic circuit that controls other elements according to given instructions and thereby advances an algorithm (process).

[0044] Brief description of the drawings 24-1264

[0045] Examples of the manifestation of the revelation are shown in the figures and are described in more detail below. They show:

[0046] Figure 1 schematically shows a network system with tasks running on a synchronous and asynchronous system, according to embodiments of the present disclosure.

[0047] Figure 2 schematically shows network cycles with an indicated TDMA schedule (or beginning and end of time slots and cycle defined by macro-ticks) of a time-controlled synchronous network system according to embodiments of the present disclosure, and

[0048] Figure 3 shows a flowchart of a communication method according to embodiments of the present disclosure.

[0049] Implementations of the revelation

[0050] Unless otherwise noted, the same reference symbols are used for identical and equivalent elements in the following.

[0051] Figure 1 schematically shows a network system 100 according to embodiments of the present disclosure. Figure 2 schematically shows network cycles of the synchronous bus system 110 in the network system 100.

[0052] The network system 100 comprises at least one synchronous bus system 110 to which at least one first network component is connected (in the example of Figure 1, two first network components 112a, 112b are shown), wherein the at least one synchronous bus system 110 is configured for task-synchronous operation according to a bus schedule; at least one asynchronous bus system 120 to which at least one second network component is connected (in the example of Figure 1, two second network components 122a, 122b are shown); and a gateway 130, which is connected via corresponding 24-1264

[0053] Interfaces 132, 132b are connected to the at least one synchronous bus system 110 and the at least one asynchronous bus system 120 and are set up to provide a time base for the at least one asynchronous bus system 120, which is derived from the bus schedule of the synchronous bus, for task synchronization.

[0054] The synchronous bus system acts as the central clock source for all connected network components, such as control units, and precisely defines when specific tasks and / or message transmissions take place. This type of communication is based on a fixed schedule, such as the so-called TDMA schedule (Time-Division Multiple Access Schedule), which ensures deterministic and predictable control. Network components connected to this synchronous bus precisely align their internal processes and task execution with this schedule, so that their communication always occurs at predefined times (for example, relative to a designated time slot) within the network cycle.

[0055] In contrast, an asynchronous bus system generally operates without a centrally defined time control. In such a system, network components send and receive their messages based on events, such as specific events or changes in sensor data, instead of adhering to a fixed, system-wide schedule. However, this presents a challenge when network components from both bus systems need to interact deterministically. While network components on the synchronous bus communicate in precisely defined time slots, data transmission on the asynchronous bus occurs unpredictably and / or without precise coordination with other network components.Even if a network component operates cyclically on the synchronous bus, its local time drifts relative to the time base of other network components (on both the synchronous and asynchronous buses) and the TDMA schedule. Without further measures, synchronization is lacking. This lack of synchronization can lead to time-critical tasks being executed unreliably or not at the correct time. 24-1264.

[0056] To solve this problem, the gateway ("TDMA-Timing-aware Gateway") is provided according to the embodiments of the present disclosure. This gateway acts as a link between the synchronous and the asynchronous bus and ensures that the network components on the asynchronous bus also receive a time base that is oriented towards the clock of the synchronous bus and adequately substitutes it. This enables cross-system synchronization, so that tasks can be orchestrated in a time-aligned manner across both bus systems, thereby enabling fully deterministic system behavior.

[0057] The gateway is connected to both bus systems and continuously synchronizes with the TDMA schedule of the synchronous bus. The gateway can also access the TDMA schedule and generate a derived time base based on it, which serves as a reference for the network components on the asynchronous bus. If this derived time base is regularly passed on to the connected network components, they can align their own task synchronizations with it. This creates an indirect, yet structured mechanism by which even an originally asynchronous bus system acquires a form of temporal order or a time understanding that corresponds to the time understanding of the synchronous bus. With this cross-system time understanding, tasks can be synchronized across system boundaries in a heterogeneous system.

[0058] Synchronization between the synchronous and asynchronous buses is achieved through continuous correlation between the TDMA schedule of the synchronous bus and the gateway's local time, followed by correction of the offset. The gateway continuously measures the time difference between its own local time and the last relevant timing event from the synchronous bus, such as a scheduled data transmission within a specific time slot. Based on this measurement, the gateway can determine how far its own internal time deviates from the system-wide reference time of the synchronous bus and correct the offset by adjusting its local time.

[0059] Correct. The adjusted local time is distributed as the time basis for synchronizing the tasks on the asynchronous bus.

[0060] To ensure that this time difference does not accumulate over multiple network cycles, the gateway's local time is cyclically realigned and continuously distributed across the asynchronous bus. First, the local time is correlated with the TDMA schedule using cross-timestamping. This correlation allows, for example, the determination of the local time at the start of the next TDMA cycle. The TDMA timing-aware gateway then corrects the local time so that it is a multiple of the cycle time itself at the start of the next TDMA cycle. During this process, the ATDD offset between the start of the next cycle (or any suitable timing event on the synchronous bus, such as a designated time slot) and the gateway's current local time is adjusted so that it equals zero modulo the cycle time or cycle length of the synchronous bus.This means that the gateway adjusts its (local) time base so that it exactly matches the system clock of the synchronous bus at regular intervals before it is distributed.

[0061]

[0062] where (assuming that local time and global time at the gateway are identical), the time at the start of the next cycle is given by the correlation between local time and the TDMA schedule as follows:

[0063]

[0064] Based on these measurements, the gateway can generate, maintain, and update a time tuple that manages the local time and the corresponding derived time base used for task synchronization of the asynchronous bus system:

[0065]

[0066] TnextCyc represents the local time at the beginning of the next cycle, whereas TnextCyc-ATDD denotes the corrected time that is distributed as a time base on the asynchronous bus for system-wide task synchronization. A continuous resynchronization mechanism continuously compensates for the ATDD offset, ensuring that the time base distributed by the gateway is always restored to the original timeframe of the synchronous bus. This results in stable and long-term synchronization, where the asynchronous bus system does not directly adapt to the synchronous schedule, but receives a derived time base that serves as a reliable reference for the network components on the asynchronous bus and can be used as the basis for fully deterministic system behavior.

[0067] The result of this synchronization is that both the synchronous and asynchronous bus systems operate in the same time-controlled rhythm. Network components connected to the different bus systems can thus execute their tasks in a coordinated manner across systems, without unwanted delays or inconsistencies in data transmission. This is particularly crucial in highly networked vehicle systems, as modern vehicles increasingly use various communication protocols in parallel.

[0068] Without such a gateway, it could happen, for example, that a control unit on the synchronous bus sends safety-critical information, such as an emergency braking request, within a specific time slot, while the receiving control unit on the asynchronous bus reacts with a delay because it does not operate on the exact same time base. The gateway underlying this invention eliminates this potential risk, as all control units—regardless of whether they are on the synchronous or asynchronous bus—now operate within a consistent timeframe. Overall, the gateway ensures that even in hybrid network topologies where both synchronous and asynchronous bus systems exist, uniform and coherent timing is maintained. This leads to more reliable and predictable task orchestration, which is particularly advantageous in safety-critical and time-critical applications.

[0069] Figure 3 schematically shows a flowchart of a communication method 300 according to embodiments of the present disclosure. The communication method 300 can be implemented by appropriate software that can be executed by one or more processors (e.g., a CPU).

[0070] The communication method comprises, in block 310, determining, by a gateway connected to at least one synchronous bus system and at least one asynchronous bus system, a time base for the at least one asynchronous bus system for task synchronization based on a bus schedule of the at least one synchronous bus system; and in block 320, distributing the time base thus derived on the at least one asynchronous bus system and executing tasks by at least one network component connected to the at least one asynchronous bus system, based on the time base provided by the gateway and derived from the synchronous bus system.

[0071] The synchronous bus system thus provides a clock signal according to which the connected network components execute their tasks. All network components connected to this synchronous bus system synchronize their tasks according to the predefined bus schedule of the synchronous bus, ensuring deterministic and coordinated task execution.

[0072] The gateway, which is connected to both the synchronous and asynchronous bus systems, derives a synchronized time base based on the bus schedule. This time reference serves as an orientation for the network components on the asynchronous bus system, enabling them to align themselves with the system clock provided by the synchronous bus system.

[0073] The network components connected to the asynchronous bus system adopt this derived time base to synchronize and time their own tasks accordingly. This ensures that uniform temporal orchestration of tasks is possible even in a hybrid network with synchronous and asynchronous bus systems.

[0074] Although the invention has been further illustrated and explained in detail by means of preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived from them by a person skilled in the art without departing from the scope of protection of the invention. It is therefore clear that a multitude of possible variations exist. It is also clear that the embodiments mentioned as examples are truly only examples and are not to be understood in any way as limiting, for example, the scope of protection, the possible applications, or the configuration of the invention.Rather, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete terms, whereby the person skilled in the art, with knowledge of the disclosed inventive concept, can make various changes, for example with regard to the function or the arrangement of individual elements mentioned in an exemplary embodiment, without leaving the scope of protection defined by the claims and their legal equivalents, such as further explanations in the description.

Claims

24-1264 Patent claims 1. Network system (100), comprising: at least one synchronous bus system (110) to which at least one first network component (112a, 112b) is connected, wherein the at least one synchronous bus system (110) is configured for task-synchronous operation according to a bus schedule; at least one asynchronous bus system (120) to which at least one second network component (122a, 122b) is connected; and a gateway (130) which is connected to the at least one synchronous bus system (110) and the at least one asynchronous bus system (120) and is configured to provide a time base for the at least one asynchronous bus system (120) for task synchronization based on the bus schedule, so that the at least one asynchronous bus system (120) is also configured for task-synchronous operation using the time base.

2. Network system (100) according to claim 1, wherein: that at least one synchronous bus system (110) includes or is a FlexRay bus system; and / or that includes or is at least one asynchronous bus system (120) a CAN bus system or an Ethernet system.

3. Network system (100) according to claim 1 or 2, wherein the bus schedule is a Time-Division Multiple Access, TDMA, schedule.

4. Network system (100) according to one of claims 1 to 3, wherein the at least one asynchronous bus system (120) exhibits fully deterministic system behavior in task-synchronous operation.

5. Network system (100) according to any one of claims 1 to 4, wherein the gateway (130) is configured to: 24-1264 to generate the time base by the gateway (130) continuously determining a time interval between its own local time and a last relevant timing event from the at least one synchronous bus system (110) and correcting any offset by adjusting the local time, and the adjusted local time is distributed as the time basis for synchronizing the tasks on the at least one asynchronous bus system (120).

6. Network system (100) according to claim 5, wherein the gateway (130) is configured to adjust the local time so that at the start time of a next cycle it is a multiple of the cycle time itself.

7. Network system (100) according to claim 5 or 6, wherein the gateway (130) is configured to generate a time tuple comprising the local time and the correspondingly derived time base used for task synchronization of the at least one asynchronous bus system (120).

8. Vehicle, in particular motor vehicle, comprising the network system (100) according to any one of claims 1 to 7.

9. Communication procedure (300) for a network system (100), comprising: Determine or derive (310) a time base for the at least one asynchronous bus system (120) for task synchronization based on a bus schedule of the at least one synchronous bus system (110) by means of a gateway (130) connected to at least one synchronous bus system (110) and at least one asynchronous bus system (120); and Execution (320) of tasks by at least one network component (122a, 122b) connected to the at least one asynchronous bus system (120), based on the derived time base provided by the gateway (130).24-1264 10. Storage medium comprising a software program configured to run on one or more processors and thereby to execute the communication method (300) according to claim 9.

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