DE102009057773A1 - Method and device for monitoring data transmission in a vehicle - Google Patents

Abstract

A method and a device for monitoring a data transmission in a vehicle are specified in which a transmission quality is determined and a predetermined action is performed depending on the determined transmission quality. Furthermore, a vehicle is proposed with such a device.

Description

The invention relates to a method and a device for monitoring a data transmission in a vehicle. Furthermore, a vehicle is proposed with such a device.

The transmission of analog or digital data in a vehicle (eg via a bus system of the vehicle) can be disturbed in different ways.

For example, it is possible that interference occurs due to crosstalk of individual cables or that an external interferer degrades the transmission quality. Also, aging effects or temperature changes can affect the transmission quality. Since the vehicle must operate in different environments and over a long period of time, the data transmission or the components involved in the data transmission are dimensioned so that a functionality is guaranteed under all defined boundary conditions.

In accordance with these boundary conditions, sufficient reserves are thus kept available, so that the data transmission still works even if the greatest possible interference is assumed. However, this maximum interference is less likely to occur in practice, rendering the data transmission system inefficient in terms of average operating requirements.

In addition, it is disadvantageous that the design of the data transmission system in practice is often designed without detailed knowledge of the real fault but with sufficient reserves that may never be needed in the vehicle even under high interference.

Accordingly, ignorance of possible interference and inadequate design of the system can also lead to errors in the data transmission, which are only recognized when they occur.

Due to the very low bit error rate of a digital bus system used in a vehicle, it is difficult to detect an increasing bit error rate, in particular because the bit errors occur very rarely even in the event of a fault.

For example, with a data transfer rate of 10 Mbps, it takes about 10 ⁴ seconds, or about 2.8 hours, until a single error is observable. Because of this relatively long observation period, troubleshooting is almost impossible.

However, even a rare error can affect an essential function of the vehicle and is therefore extremely undesirable.

The object of the invention is to avoid the above-mentioned disadvantages and in particular to provide an efficient way of monitoring a data transmission system or a part of such a system in a vehicle.

This object is achieved according to the features of the independent claims. Further developments of the invention will become apparent from the dependent claims.

• – bei dem eine Übertragungsqualität ermittelt wird,
• – bei dem abhängig von der ermittelten Übertragungsqualität eine vorgegebene Aktion durchgeführt wird.

To achieve the object, a method for monitoring a data transmission in a vehicle is proposed,

• - in which a transmission quality is determined,
• - In which depending on the determined transmission quality, a predetermined action is performed.

Thus, it is particularly advantageous that a transmission error can already be detected before it actually occurs. It is also possible that deteriorations in the transmission quality can be suitably evaluated and used to design the communication system.

A development is that the transmission quality is determined in a control unit of the vehicle.

In particular, the control unit can for this purpose have a processing unit and a transceiver. Preferably, the controller is coupled to a bus system of the vehicle. The bus system may be an Ethernet bus.

Another development is that the control unit is connected via a bus system of the vehicle with at least one further control unit.

• – eines Signalrauschabstands;
• – eines Signalstörverhältnisses;
• – ein digital berechneter Fehlerwert.

In particular, it is a development that the transmission quality is determined using at least one of the following variables:

• - a signal to noise ratio;
• - a signal interference ratio;
• - a digitally calculated error value.

It is also a development that the predetermined action includes an adjustment of the transmission rate.

Furthermore, it is a development that the predetermined action includes an adjustment of the error correction.

In the context of an additional development, the predetermined action comprises a storage of the transmission quality and / or the change of the transmission quality.

A next development is that a type, a position and / or an extent of a disorder is / are stored.

An embodiment is that the predetermined action comprises a storage of a transmission error.

An alternative embodiment is that the predetermined action includes communication with another controller.

A next embodiment is that the predetermined action is performed before a transmission error occurs.

It is also an embodiment that the transmission quality is determined continuously or in predetermined time-discrete steps.

The above object is also achieved by means of a device comprising a processing unit which is set up in such a way that the method described herein can be executed.

The processing unit may, for. It may be implemented as a processor and / or at least partially hard-wired circuitry arranged to perform the method as described herein.

The processor may be or include any type of processor or computer or computer with correspondingly necessary peripherals (memory, input / output interfaces, input / output devices, etc.). Furthermore, a hardwired circuit unit, for. As an FPGA or an ASIC or other integrated circuit may be provided.

A next embodiment is that the device is a control unit or part of a control device of a vehicle.

Also, the above object is achieved by means of a vehicle comprising at least one of the devices described herein.

Embodiments of the invention are illustrated and explained below with reference to the drawings.

Show it:

1 a schematic block diagram of a control device in a vehicle, in which also takes place a determination of the signal to noise ratio;

2 a schematic arrangement of several interconnected ECUs in a vehicle.

The approach proposed here enables proactive fault detection in a bus system of a vehicle. This is achieved in particular by a continuous monitoring of the transmission quality.

By means of a transceiver (i.e., a combination of transmitter and receiver), a signal-to-noise ratio (signal-to-noise ratio - SNR, signal-to-interference distance SNIR) can be determined, in particular measured and / or calculated, during the data transmission.

Based on the signal to noise ratio, the transmission quality can be determined in a predefinable resolution or granularity. In this case, it is advantageous that the transmission quality can be determined during the data transmission and thus a predetermined action can be carried out when an error occurs (for example in the event of a deterioration in the signal-to-noise ratio).

For example, the disturbance (type, location and / or extent of the disturbance) can be stored or it can be reacted to the disturbance. The fault may also be a transmission error, eg. B. one (or more) bit errors.

Thus, in case of error, z. B. when falling below a predetermined threshold for the signal-to-noise ratio, during the data transmission, a fault memory are set and / or measures can be taken to respond to the error (and thus to the fault). For example, a retransmission may be requested or an error correction means may be activated and / or increased. The error correction means may preferably be designed so that, due to redundant information, the data is at least partially reconstructable at the receiver, even if some of the data has been corrupted due to the interference.

One advantage is that the reaction to the fault is localized, that is to say in that of the Disorder affected area, can be done. It is also advantageous that even a detection of a disturbed data transmission is possible before it comes to a transmission error. In modern bus systems bit error probabilities z. From 10 ^-10 , so that degradation of the data transmission can already be countered before an actual communication error occurs.

Thus, the approach presented here makes it possible to detect a transmission error (sampling rates, for example, in the range of milliseconds); it is not necessary to wait several hours in the perhaps unlikely event of error occurrence.

1 shows a schematic block diagram of a controller 101 in a vehicle in which a determination of the signal-to-noise ratio also takes place. The control unit 101 includes a processor unit HOST 102 , a transceiver 104 (comprising a transmitter and a receiver) connected to a bus 105 of the vehicle and a monitor 103 ,

The transceiver 104 transmits bus parameters to the monitor 103 , which determines the signal-to-noise ratio preferably (almost) in real time on the basis of these bus parameters. The signal-to-noise ratio can then be sent to the processor unit HOST 102 forwarded for further evaluation. Depending on the signal-to-noise ratio, the processor unit may be HOST 102 z. B. the transceiver 104 influence the data rate provided. It is also possible that the processor unit is HOST 102 Information regarding the signal to noise ratio stores so that they can be evaluated later.

• – zusätzliche Daten überträgt, die eine verbesserte Fehlerkorrektur ermöglichen (z. B. mehr redundante Daten um die Möglichkeiten der Bitfehlerkorrektur zu verbessern);
• – weiteren Steuergeräten mitteilt, dass diese entsprechend auf einen Modus mit einer höheren Fehlerkorrektur umschalten sollen;
• – einer zentralen Steuereinheit mitteilt, dass ein Übertragungsfehler bevorsteht;
• – einer zentralen Steuereinheit mitteilt, dass ein Übertragungsfehler eingetreten ist;
• – einer zentralen Steuereinheit die ermittelte Übertragungsqualität mitteilt.

Due to the monitoring of the signal to noise ratio, it is thus possible to detect early gradual deterioration of the transmission and thus impending transmission errors. Accordingly, appropriate measures can be taken in particular for safety-related functions of the vehicle: For example, the control unit of a gradual deterioration z. B. due to aging effects, temperature variations, interference from external sources, etc. counteract by the processor unit HOST 102 z. B.

• - transmits additional data that allows for improved error correction (eg more redundant data to improve the capabilities of bit error correction);
• - tells other ECUs that they should switch accordingly to a mode with a higher error correction;
• - notifies a central control unit that a transmission error is imminent;
• - notifies a central control unit that a transmission error has occurred;
• A central control unit communicates the determined transmission quality.

Accordingly, it is also possible that the processor unit HOST 102 stores the determined transmission qualities and this z. B. provides a control device when needed.

Also, the processor unit can HOST 102 Reduce the redundancy information for the error correction (or communicate this to the units involved in the communication, for example, control units), if it is determined that the transmission quality improves again.

It should be noted that the signal-to-noise ratio mentioned here is only mentioned by way of example as a possible measure by means of which the transmission quality can be determined. Accordingly, other sizes, eg. As a signal interference ratio or a (digital or analog) calculated error value, also be used in combination with each other or with the signal to noise ratio.

2 shows a schematic arrangement of several control devices 201 to 205 in a vehicle that are interconnected.

In the example of 2 is the control unit 201 with the control units 202 and 203 connected, the control unit 202 is still with the control units 204 and 205 connected and the control unit 204 is also with the control units 205 and 203 connected.

An example is the connection between the control unit 201 and the controller 202 disturbed or it comes to this connection to a deterioration of the transmission quality without a transmission error would already occur (see fault 206 ).

According to the present solution, both controllers 201 . 202 the nature, location and extent of the disturbance 206 recognize and react accordingly.

Also, it is an option that, starting from a certain degree of degradation in transmission quality, both controllers 201 . 202 (or each of these controllers for themselves) choose an alternative communication route to the respective other controller. Thus, a possible transmission error can be efficiently reacted before it actually occurs.

(Other advantages:

The continuous determination of the signal-to-noise ratio makes it possible to detect impairments in the data transmission even before the error occurs and the undesired consequences of such a fault in the vehicle become apparent.

Thus, it is possible to quantify and locate disturbances. Preferably, a threshold for the still acceptable signal to noise ratio can be set so that the transmission system in the vehicle detects an error.

In particular, the transmission system in the vehicle need not be designed in advance with large safety margins for perhaps the most unlikely greatest possible disturbance, but the transmission system itself may respond to disturbances (eg, dynamic).

The continuous determination of the signal-to-noise ratio significantly increases the robustness of the overall system and reduces unnecessary safety margins and associated costs.

LIST OF REFERENCE NUMBERS

101

control unit

102

Processor unit HOST

103

monitor

104

transceiver

105

bus

201

control unit

202

control unit

203

control unit

204

control unit

205

control unit

206

disorder

Claims (15)

Method for monitoring data transmission in a vehicle, - in which a transmission quality is determined, - In which depending on the determined transmission quality, a predetermined action is performed. The method of claim 1, wherein the transmission quality is determined in a control unit of the vehicle. Method according to Claim 2, in which the control unit is connected to at least one further control unit via a bus system of the vehicle. Method according to one of the preceding claims, in which the transmission quality is determined on the basis of at least one of the following variables: - a signal to noise ratio; - a signal interference ratio; - a digitally calculated error value. Method according to one of the preceding claims, in which the predetermined action comprises an adaptation of the transmission rate. Method according to one of the preceding claims, in which the predetermined action comprises an adaptation of the error correction. Method according to one of the preceding claims, in which the predetermined action comprises a storage of the transmission quality and / or the change of the transmission quality. Method according to one of the preceding claims, in which a type, a position and / or an extent of a disturbance is / are stored. Method according to one of the preceding claims, wherein the predetermined action comprises a storage of a transmission error. Method according to one of the preceding claims, wherein the predetermined action comprises a communication with a further control unit. Method according to one of the preceding claims, wherein the predetermined action is performed before a transmission error occurs. Method according to one of the preceding claims, in which the transmission quality is determined continuously or in predetermined time-discrete steps. Device having a processing unit, which is set up such that the method according to any one of the preceding claims is executable. Device according to Claim 13, in which the device is a control device or part of a control device of a vehicle. Vehicle with a device according to one of claims 13 or 14.

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