KR20140064646A - Method for testing of receiving a message in a terminal - Google Patents

Abstract

The present invention relates to a method for testing the reception of a message in a terminal (200), comprising a step of determining a receiving point (tE,0) when the terminal receives a message using a communication unit (100); a step of determining an analyzing point (tA,0) when the message is analyzed by the terminal; and a step of creating the difference (Δtx) between the receiving point and the analyzing point and determining whether an error exists in receiving the message based on the difference (Δtx).

Description

TECHNICAL FIELD [0001] The present invention relates to a method for checking a message received from a terminal,

The present invention relates to a method for checking message reception in a terminal.

In recent vehicles, a plurality of control apparatuses that intensively communicate with each other are used. In addition to standard communications over the so-called Controller Area Networks (CAN), FlexRay networks are also increasingly being used for rapid and secure information exchange.

A FlexRay bus is a time-controlled bus that can transmit information (messages) between a first terminal (e.g., a control device) and a second terminal. The message may be transmitted in a predetermined time frame (e.g., every 10 ms) or on an event basis (e.g., depending on the number of rotations).

In addition to the actual message content, it is important for the receiving terminal, particularly in the case of safety critical data, to know whether the transmitting terminal is still operating properly and is transmitting the latest data and whether the transmission has been performed without error.

The terminals and the FlexRay bus each operate in a clock controlled manner. In this case, the transmitting terminal provides the message with each clock pulse, and FlexRay bus takes over the message provided from the transmitting terminal with each clock pulse, and transmits the message to the receiving terminal. Finally, the receiving terminal analyzes each message sent from the FlexRay bus using each clock pulse.

Even when the clock frequencies are the same, since the clocks of the FlexRay bus (more specifically, the bus driver) and terminals are each based on one inherent time base, the clock pulses of the elements can be periodically mutually offset. The clock frequency and the respective time axes together preset the time at which each element (FlexRay bus or terminal) can become active.

In an optimal case, it is desirable that the FlexRay bus be able to take over and forward the message at the same time that the sending terminal supplies the message, and so that the recipient terminal can analyze the message at the moment FlexRay bus can supply the message , The time axes are mutually adjusted.

However, in reality, the time axes are offset from each other, resulting in a delay (waiting time) in transmission.

The assumption that the clock is observed and the resulting periodicity of displacement are not realistic. Rather, so-called jitter occurs, in other words, when the clock adheres, the accuracy varies due to the participating elements. For example, even if the receiving terminal and the FlexRay bus are set to each other for optimal conditions (as described above) (thereby theoretically exactly at the time the clock of the FlexRay bus presets the transmission, , The receiving terminal can only analyze the message if and only if the FlexRay bus actually provides the message up to the point in time at which it was provided for this purpose. Conversely, a message at a delay can only be analyzed from the receiving terminal by the next clock pulse of the terminal. Likewise, at the receiving terminal, the analysis time may be modified by the changing computing load. This also applies to the interaction between the FlexRay bus and the transmitting terminal. The specified faults should be considered in the case of debouncing the message counter at the receiving terminal, i.e., checking if the message was received periodically or whether the message content is still up-to-date. If an error response is to be initiated when the message is not reached, the error response will only be started after two time clocks during transmission due to the impact of jitter and the changing computing load at the receiver, to prevent a response error (improper error response) . For example, other permissible deviations and delays in the chain signal at the transmitting terminal are still not considered.

In particular, the need for safety for hybrid vehicles is being increasing to identify fault conditions more and more quickly and to quickly activate preset fault responses. In addition, due to the increase in bus load, the message is moved to a partially slower time frame, so that all clock loss becomes more important until an error is identified.

It is therefore an object of the present invention to provide a possibility of shortening the waiting time in reliable monitoring of a communication system.

According to the present invention there is provided a method of inspecting the reception of a message in a terminal having the feature of claim 1. Preferred embodiments are subject of the dependent claims and the following specification.

The present invention shortens the identification period until a defect can be confirmed from the receiving terminal in the communication system (that is, the transmitting terminal or the communication means). At this time, there is no need to wait for three or more unreached information. Rather, the present invention is used for an inspection function for analyzing a reception time point, that is, a time point at which a message or information is received from the terminal, and determines a deviation at an analysis time point, that is, a time point at which a message is processed in the terminal. Based on this deviation, it is possible to identify whether the analysis is performed within the scope of time allowed after reception, in particular by threshold comparison.

For this, a time interval preferably having a lower limit and an upper limit can be confirmed, and the following contents apply to the time interval. If the deviation is below the lower limit, normal function can be confirmed. If the deviation is above the upper limit, it can be confirmed that there is an error. If the deviation is within the interval, it can not be determined, so the checking function must be recalled at a later time, preferably at the next clock interval. Then, at this next clock interval, since the time between the last received message and the latest analysis time is clearly above the upper bound of the allowed time interval, a new message may be given or the error message may be reliably blocked.

If the deviation between the analysis time point and the reception time point is within the interval, the time until the next call of the inspection function is preferably shortened. For example, the check function may be re-invoked after a half clock interval already. This allows for faster identification of errors.

The timing of message reception and message processing at the terminal (which approximately correspond to the bus and the status of the clocks in the terminal) has not been analyzed so far. This means that the application of the debounce time in the time-based analysis is extended by a time clock to prevent jitter effects that may occur, in order to monitor the message at the terminal. When the time clocks are positioned so that a jitter effect can not occur, the debounce time is thereby extended unnecessarily by one clock. Debouncing means not waiting for an error response to start immediately when an error is identified, but waiting for a certain amount of time (debouncing time) / number of function calls. If the error disappears again during this time (for example, if a new message appears again), no error response is activated.]

The results of the present invention can limit this additional debouncing clock to cases where a jitter offset may actually occur by analyzing the message reception time and processing time at a terminal (e.g., a control device of an automobile). Thus, in most of the above cases, the necessary debouncing time can be reduced by one time clock.

Preferably, a decision clock interval is determined which determines whether there is an error in the communication system. Where the clock interval may be the latest clock interval with a deviation determined according to the deviation, or a clock interval immediately following each (in relation to the terminal clock).

The present invention is particularly well suited for use in FlexRay buses because FlexRay buses provide a time base. As a result, the measurement of the reception time point can be made particularly simple. However, the present invention can be advantageously used in other bus systems such as CAN. In this case, a corresponding terminal device is required to confirm the reception timing in some cases.

In a first alternative, for example, a FlexRay driver module in a terminal stores in addition to the message a point in time at the inherent timebase of the point of time of reception. The offset of the time axis is used to switch from the terminal to the terminal time base. The offset may be determined during operation.

In a second alternative, for example a FlexRay driver module in a terminal, recalls the latest terminal time on the terminal time base upon receipt of the message and further stores the terminal time in the message.

In a third alternative, for example, a FlexRay driver module or CAN driver module in a terminal triggers the terminal upon receipt of a message, and the terminal stores the reception time on the terminal time base.

The control unit of a computer unit according to the present invention, for example an automobile, is particularly adapted to carry out the method according to the invention by means of a program description.

It is also desirable to implement the method of the present invention in the form of software, especially if the execution control device has already been used for other tasks, which results in very low costs. Suitable data carriers for providing computer programs are, in particular, diskettes, hard disks, flash memories, EEPROMs, CD-ROMs, DVDs, and the like. It is also possible to download programs via a computer network (Internet, intranet, etc.).

Other advantages and configurations of the present invention refer to the specification and the accompanying drawings.

The features mentioned above and described below can be used within the scope of the present invention, in the form of each specified combination as well as another combination or alone.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is schematically illustrated in the drawings on the basis of an embodiment and is described in detail below with reference to these figures.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram illustrating the process of a preferred embodiment of a method according to the present invention;

In Figure 1 a preferred embodiment of the method according to the invention is shown with time. Each numbered clock interval 10 in the figure is shown according to time t. The upper temporal line 100 here represents the time axis of the communication means formed on the FlexRay bus (comprising the FlexRay driver module on the terminal) and the lower temporal line 200 represents the time axis of the communication means Lt; RTI ID = 0.0 > of the < / RTI > The communication medium and the terminal are part of a communication system and generally further comprise at least another transmitting terminal.

As mentioned in the introduction, the FlexRay the bus as well as the control device is also clock-controlled, for example, for the first time in the first in each process step are also _{1 t E, 0 = "1} " information on the time of transmission and 1 t _{A, 0} = "7 ". The terminals connected to the FlexRay bus are managed according to the "Time Division Multiple Access (TDMA)" scheme. All FlexRay driver modules on the terminals are synchronized to the same clock and wait until the clock is in order by being written to the bus.

A time frame T ₀ is identified for message transmission that is not based on events (i.e., based on conventional time), which defines the interval between two messages periodically transmitted (e.g., from another control device). Such time frames (t _{E , 0} , t _{E , 1} , ...) are generally applied depending on each message, for example, messages in which safety critical messages are transmitted more frequently, I can not. Processing of messages in the same time frame (t _{A , 0} , t _{A , 1} , ...) is also performed in the control device. Advantageously, the invocation of the checking function also basically proceeds at clock intervals of the information processing.

(T _{E , 1} ) and the processing time point (t _{E , 1} ) by a separate time base of the FlexRay bus, i. _E. The communication interface driver module of the control unit here in more detail and by the independent time base of the control unit, a somewhat large clock interval displacement? ₀ (< T ₀ ) can be generated between the clock signals t _{A and} T _A.

The maximum time (T _{0 , maximum} ) between two messages during normal operation caused by jitter on the bus can reach (T _{0 , maximum} = T ₀ + T _{jitter , maximum} ), where T _{jitter ,} (Indicated by T _j in the figure).

In a preferred embodiment, the calculation execution time (T _{execution time} ) (indicated by T _L in the figure) between reception and processing of a message at the receiving control device may be further considered. Another jitter is caused by the fluctuation of the calculation load, and the calculation execution time is between the T _{execution time, the minimum} and the T _{execution time, and the maximum} . This is the delay time (△ t _{x. Max)} between the received messages that are expected to be maximum in normal operation and analysis (△ t _{x. Up to} T = _{0, max} + T _{time, maximum).}

Since the states of the clocks are not known to each other, it is always necessary to wait for the message to fail to consider the jitter effect when monitoring the message without measuring the time. This results in a minimum (Δt _{x . Error} = 2 * T ₀₎ , depending on the state of the bus clocks and the controller clocks, from the last valid message input to the identification of the message failure _. + T _{execution time, minimum} ) and maximum (Δt _{x . Error} = 3 * T ₀ + T _{execution time, maximum} ).

The present invention provides the possibility of shortening this delay time by monitoring the time. To this end, the points of message reception and processing are measured and further stored in the message.

The delay time (t _x = t _{x . Analysis} - t _{x , reception} ) is shorter than Δt _{x . max} in normal operation.

In these considerations, the following cases can be distinguished when calling the test function.

a) Δt _x <T ₀ + T _{execution time, minimum} -T _{jitter , maximum}

In this case, at the instantaneous analysis clock interval, it can be reliably identified that the processed message is up-to-date. Therefore, the instantaneous analysis clock interval is the determined clock interval (i.e., the clock interval that determines whether the communication system is operating correctly or error-wise).

b) T ₀ + T _{execution time, minimum} -T _{jitter , maximum} <Δt _x <T ₀ + T _{execution time, maximum} + T _{jitter , maximum}

In this case, at the instantaneous analysis clock interval, it can not yet be reliably identified whether the processed message is up-to-date. The check function is recalled at a later time. This is preferably the latest analytical clock interval at the latest. However, the test function may be re-invoked after the analysis clock interval, e.g., already half the analysis clock interval, to accelerate the decision.

c) Δt _x > T ₀ + T _{execution time, maximum} + T _{jitter , maximum}

In this case, at the instantaneous analysis clock interval, it can be reliably identified that the processed message is not up-to-date. The transmitting terminal and / or the communication means do not operate without error. Therefore, the instantaneous analysis clock interval becomes the decision clock interval.

Thus, the message failure is already identified when it exceeds the threshold of T ₀ + T _{execution time, maximum} + T _{jitter , maximum} .

This means that a 10ms message clock and a total jitter of ± 1ms will already be able to identify a message failure in the first occurring error message when the time offset is already distributed from 11ms, ie 90% of the cases, between the reception time and the analysis time have. The remaining unclear cases can certainly be evident at the next clock call.

Claims (16)

A method of inspecting the reception of a message in a terminal (200)
- determining the time of reception (t _{E , 0} ) at which the terminal received the message via the communication means (100)
- determining an analysis time (t _{A , 0} ) at which an analysis of the message is made by the terminal,
Forming the difference (△ t _x) between the analysis start point and the reception point, -
- determining whether there is an error in the reception of the message, in dependence on the deviation (? T _x ). The method of claim 1, further comprising: an error in the message received no determined depending on the deviation (△ t _x) whether is a comparison with the pre-set time intervals and the deviation (△ t _x) having a lower and upper gap A method for checking the reception of a message on a terminal. 3. The method of claim 2, wherein the upper interval of the predetermined interval is calculated as a sum of at least the clock length of the communication means (100), the maximum calculation time for the message, and the maximum jitter time. 4. The method of claim 2 or claim 3, wherein the message is sent to the terminal (200) via the bus (100) and the predetermined interval is a closed interval, the length of the interval being at least one of a bus, a terminal, A method of checking the receipt of a message at a terminal that is at least twice the maximum jitter time. 4. The method according to claim 2 or 3, wherein if the deviation (DELTA t _x ) is shorter than the lower limit interval, it is determined that there is no error in message reception. According to claim 2 or 3, wherein when the upper limit is longer than the distance deviation (△ t _x), checking method of receiving messages in a terminal, it is determined that there is an error in the message received. 4. The method of any one of claims 1 to 3, wherein an error routine is initiated if there is an error in message reception. 4. The method of any one of claims 1 to 3, wherein the method is re-executed at a later time when the deviation (AT _x ) is located within a predetermined time interval. 9. The method of claim 8, wherein the later time point is the processing clock of the terminal immediately following. To claim 1, wherein the step of determining whether or not according to any one of claim 3, wherein, depending on the deviation (△ t _x) there are no errors in the message received,
- determining a decision clock interval (t _{A , 0} , t _{A , 1} ) in dependence on the deviation (? T _x )
- determining at a decision clock interval (t _{A , 0} , t _{A , 1} ) whether or not there is an error in receiving the message. 11. The method of claim 10, wherein the analysis time point is located within an analysis clock interval,
- confirming that the deviation (DELTA t _x ) is not located within a predetermined time interval, confirming the decision clock interval as the analysis clock interval,
- the deviation (△ t _x) is a predetermined time and confirmed that the position in the interval, a method of checking a message received on the device, which comprises a check to determine clock intervals immediately following clock interval in clock analysis interval. The method of claim 11, wherein the terminal is configured to determine that the deviation (△ t _x) are not located in a predetermined time interval,
- if it is ascertained that the deviation &lt; RTI ID = 0.0 & gt _; (Delta _x ) & lt _; / RTI &gt; is longer than the upper bound of the given time interval,
- When the deviation (△ t _x) is ascertained that the upper limit is less than the spacing of the given time interval in advance, the message received is a test method for receiving, from the terminal a message further comprises: determining that there is no error. 4. A method according to any one of claims 1 to 3, wherein the communication means is a FlexRay bus or a CAN bus. 14. The method of claim 13, wherein determining the receive time (t _{E , 0} )
- calculate the receive time (t _{E , 0} ) on the terminal time axis by the FlexRay driver module from the time of receipt of the message stored in the FlexRay timebase from the FlexRay driver module and from the time axis offset between the FlexRay timebase and the terminal timebase,
- calculate the time of reception (t _{E , 0} ) on the terminal time base by the terminal from the time of receipt of the message stored in the FlexRay time axis from the FlexRay driver module and from the time axis offset between the FlexRay time axis and the terminal time axis,
- activating the terminal to determine the time of reception (t _{E , 0} ) by the FlexRay driver module or the CAN driver module upon receipt of the message. A computer unit installed for carrying out the method according to any one of claims 1 to 3. A computer program having program code means for causing a computer unit to execute a method according to any one of claims 1 to 3 when executed on a computer unit.

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