DE102006059627A1 - Method and system for transmitting data frames - Google Patents

Abstract

The present invention provides a method of transmitting data frames each comprising at least one header segment and a data segment having at least one data unit to be backed up having a predetermined data segment position in the data segment and a predetermined number N of data unit bits, and a checksum segment Method includes: providing a predetermined number M of data frames to be transmitted; - For a predetermined number X, with X epsilon [1, ..., M], each bitwise XOR-linking the data unit bits each at a predetermined data unit position of a predetermined amount M ', with M' <= M, provided, to be transmitted data frame for providing N check bits for a test frame to the respective set M '; - respectively storing the N check bits at the corresponding data unit positions of a further data frame to provide the test frame to the respective set M 'of provided data frames to be transmitted; and - transmitting the M data frames and the X test frames over a bus system using time division multiplexing; Receiving and checking / replacing the missing data frame.

Description

STATE OF THE ART

The The present invention relates to a method and system for transmission of data frames, in particular by means of a Flexray bus.

The Flexray bus and the associated Flexray protocol are for example in the document EP 1 355 456 A1 described.

According to the with a time-multiplexed flexray protocol Data frames or frames in one Communication cycle or cycle with a static segment and / or transmitted to a dynamic segment.

in the For purposes of this application, the terms data frame, frame, frame, Frame, message and message are synonymously related and refer to the same thing.

One Data frame contains a header segment (header), a data segment (Payload) and a checksum segment (CRC Data). A data segment includes one or more data units which may also have a different size. Of the Frame or data frame is from a first transceiver or node, the coupled to the flexray bus to at least a second transceiver or node that is also coupled to the Flexray bus.

The transferred Frames are with the CRC checksum (CRC, Cyclic Redundancy Check). The CRC checksums are used for error detection, theoretically they could also to correct the error, but the Hamming distance is Flexray protocol for that not enough and the computational effort would be very high. The respective CRC checksum a transferred one Data frame can thus indicate whether the transmitted data frame is correct or not correctly from the respective second transceiver was received.

Indeed falls in If a fault occurs or if there is a fault only one bit of the entire data frame or even in the absence of a Data frame always the complete data frame, since the CRC checksum is not correct is

ADVANTAGES OF THE INVENTION

The inventive method to transfer of data frames with the features of claim 1 and the inventive system for transmitting Data frame with the features of claim 12 has the advantage on that each transceiver, the one predetermined number of data frames from another, predetermined transmitting / receiving device via the coupling bus system receives or should correct exactly one of the number of data frames or restore if this is not or not correct at the respective transmitting / receiving device arrives. The incorrect arrival can preferably - as above represented by means of the respective CRC checksum be determined.

• a) Bereitstellen einer vorbestimmten Anzahl M zu sendender Datenrahmen;
• b) Für eine vorbestimmte Anzahl X, mit X ∊ [1, ..., M], jeweils bitweises XOR-Verknüpfen der Dateneinheitsbits jeweils an einer vorbestimmten Dateneinheitsposition einer vorbestimmten Menge M', mit M' ≤ M, bereitgestellter, zu sendender Datenrahmen zur Bereitstellung von N Prüfbits für einen Prüfrahmen zu der jeweiligen Menge M';
• c) jeweils Speichern der N Prüfbits an den entsprechenden Dateneinheitspositionen eines weiteren Datenrahmens zur Bereitstellung des Prüfrahmens zu der jeweiligen Menge M' bereitgestellter, zu sendender Datenrahmen; und
• d) Senden der M Datenrahmen und der X Prüfrahmen über ein Bussystem mittels eines Zeitmultiplexverfahrens.

According to the present invention, there is therefore proposed a method of transmitting data frames each comprising at least one header segment and a data segment having at least one data unit to be backed up having a predetermined data segment position in the data segment and a predetermined number N of data unit bits, and a checksum segment. the method according to the invention includes:

• a) providing a predetermined number M of data frames to be transmitted;
• b) For a predetermined number X, X ε [1, ..., M], each bitwise XOR-linking the data unit bits each at a predetermined data unit position of a predetermined amount M ', with M' ≤ M, provided to be sent data frames for providing N check bits for a test frame to the respective set M ';
• c) respectively storing the N check bits at the corresponding data unit positions of a further data frame to provide the test frame to the respective set M 'of provided data frames to be transmitted; and
• d) transmitting the M data frames and the X test frames over a bus system using time division multiplexing.

• – ein Bussystem, welches eine vorbestimmte Anzahl an Sende-/Empfangsvorrichtungen koppelt;
• – wobei mindestens eine Sende-/Empfangsvorrichtung aufweist:
• – ein erstes Mittel, welches eine vorbestimmte Anzahl M zu sendender Datenrahmen bereitstellt;
• – ein zweites Mittel, welches dazu geeignet ist, für eine vorbestimmte Anzahl X, mit X ∊ [1,..., M], jeweils eine bitweise XOR-Verknüpfung der Dateneinheitsbits jeweils an einer vorbestimmten Dateneinheitsposition einer vorbestimmten Menge M', mit M' ≤ M, bereitgestellter, zu sendender Datenrahmen zur Bereitstellung von N Prüfbits für einen Prüfrahmen zu der jeweiligen Menge M' durchzuführen;
• – ein drittes Mittel, welches die bereitgestellten N Prüfbits an den entsprechenden Dateneinheitspositionen eines weiteren Datenrahmens zur Bereitstellung des Prüfrahmens zu der jeweiligen Menge M' bereitgestellter, zu sendender Datenrahmen speichert; und
• – ein viertes Mittel, welches die M Datenrahmen und die X Prüfrahmen über das Bussystem mittels eines Zeitmultiplexverfahrens sendet.

Further, according to the present invention, there is provided a data frame transmitting system comprising at least one header segment and one data segment each having at least one additional data unit having a predetermined data segment position in the data segment and a predetermined number N of data unit bits, and a checksum segment the system according to the invention has:

• A bus system which couples a predetermined number of transceivers;
• - wherein at least one transmitting / receiving device comprises:
• A first means providing a predetermined number M of data frames to be transmitted;
• - A second means which is suitable for a predetermined number X, with X ε [1, ..., M], depending because performing a bitwise XOR operation on each of the data unit bits at a predetermined data unit position of a predetermined set M ', with M' ≤ M, provided data frames to be sent to provide N check bits for a test frame to the respective set M ';
• A third means which stores the provided N check bits at the corresponding data unit positions of a further data frame for providing the test frame to the respective set M 'of provided data frames to be transmitted; and
• A fourth means which transmits the M data frames and the X test frames via the bus system by means of time division multiplexing.

In the dependent claims find advantageous developments and refinements of specified in claim 1 and the method specified in claim 10 Systems for transferring Data frames.

According to one preferred embodiment of the invention is in each case a data frame in a slot predetermined by the time-division multiplexing method or time slot sent.

According to one preferred embodiment of the invention, the bus system is a Flexray bus system with a Flexray protocol coupling a predetermined number of transceivers in each case one cycle or communication cycle of the used Time division multiplexing at least one static area, in which at least a predetermined part of the transceiver devices each associated with at least one slot of identical length for sending data frames , and optionally has one or more dynamic ranges, in which the respective slots, each with a determinable length dynamically be assigned to at least a part of the transmitting / receiving devices.

According to one Another preferred development, the M data frames in the Static area sent. Thus, it is advantageously ensured that the M data frames are sent at predetermined times. The receiving transceivers can Thus, determine whether a respective data frame that is at a predetermined Time to arrive, also arrived. Should be exactly one these data frames do not arrive at any given time, the respective receiving transceiver can this replace according to the invention or restore.

According to one Another preferred development is a display bit in the head segment provided, wherein a positive logical value of the display bit, For example, 1 indicates that the data segment is at least one of having a secure data unit, and a negative logical value of the display bit, for example 0, indicates that the data segment has no data unit to be backed up. Thus, advantageously differentiated between data frames to be backed up and data frames not to be backed up become.

According to one another preferred embodiment, the display bit is a payload preamble indicator, which according to the Flexray protocol is provided in the header segment of a data frame.

According to one Another preferred embodiment determines the number X a number subnets of the bus system. Each subnet has one predetermined number of transmitting / receiving devices coupled by means of the bus system on, which in each case the quantity belonging to the respective subnet M 'the sent M data frame and the corresponding test frame associated with the respective subnet from a respective predetermined transceiver. Thus, you can within the network, through the bus system and through the Bus system coupled transmitting / receiving devices is formed, secure subnets are set up. Safe means in this Context that a data frame that was not or not correctly transmitted can be restored or generated. This is just the overhead an additional test framework required per subnet. If a subnet is insignificant, this means for example, by a data frame, from another subnet different, so can advantageously the test frame of the other subnet be reused. This results in the additional Advantage that a time slot is saved, resulting in a better utilization of the bandwidth of the bus system results.

According to one Another preferred embodiment is the redundant data frame or test frame with the parity to reduce the residual error probability, so as additional Safety, used.

According to a further preferred development, a checksum is calculated over at least one predetermined part of the data segment and / or the header segment and the calculated checksum is stored in the checksum segment of the data frame. Advantageously, the calculated checksum can indicate whether a transmitted data frame has been transmitted correctly or not correctly. Only from the determination of an incorrect transmission of a data frame can then advantageously the inventive initialization.

According to one Another preferred development, the bus system is designed as a Flexray bus system and the transceivers each have a flexray communication control device on.

According to one Another preferred embodiment is the at least one to be secured Data unit contained in a network management vector, the through the Flexray protocol 2.1 is defined.

According to one Another preferred embodiment, the X test frame each before the beginning of a cycle of the time-division multiplexing with a predetermined Value, for example 0, initialized.

DRAWINGS

embodiments The invention is illustrated in the drawings and in the following Description closer explained. Show it:

1 a schematic flow diagram of an embodiment of the method according to the invention;

2 a schematic block diagram of an embodiment of the format of the data frame according to the present invention;

3 a schematic representation of the generation of a test frame according to the present invention;

4 a schematic block diagram of an embodiment of the system for transmitting data frames according to the present invention;

5 a schematic flow diagram of an embodiment of a communication cycle according to the present invention; and

6 a schematic, detailed representation of the according to 5 transmitted data frame.

DESCRIPTION OF THE EMBODIMENTS

In the same reference numerals designate the same or functionally identical Ingredients.

In 1 is a schematic flow diagram of an embodiment of the inventive method for transmitting data frames DR1-DR11 shown. According to 2 The data frame DR1-DR11 to be transmitted in each case has at least one head segment KS, a data segment DS and a checksum segment PS. The data segment DS has at least one data unit DE1-DEn to be backed up. A data unit DE1-DEn to be saved has a predetermined data segment position P1-Pn in the data segment DS and a predetermined number N of data unit bits B1-B96 (see 3 ) on. Without restriction of generality shows 2 only a single data frame DR1. The following data frames DR2-DR11 described are analogous.

The method according to the invention will be described below with reference to the block diagram in FIG 1 with reference to the schematic block diagram of the format of the data frame DR1 as described above 2 and referring to the schematic block diagram of FIG 4 described. The embodiment of the method according to the invention 1 has the following method steps S1-S4:

Process step S1:

It becomes a predetermined number M of data frames DR1-DR7 to be transmitted provided. Preferably, the data frames to be transmitted are DR1-DR7 provided by a predetermined transceiver DR1.

Step S2:

For a predetermined number X, with X ε [1, ..., M], a bitwise XOR-linking XOR of the data unit bits B1-B96 is respectively performed at a predetermined data unit position DP1-DP96 of a predetermined amount M ', where M' ≤ M, provided data frame DR1-DR7 to be sent to provide N check bits for a test frame DR8-DR11 to the respective set M '. It shows 3 an exemplary schematic representation of the generation of the test frame DR8. Without loss of generality, for purposes of illustration below, M = 7, N = 96 and X = 4. M = 7 means that a predetermined transceiver, for example the first transceiver SE1 (see FIG 4 ), seven data frames DR1-DR7 to be transmitted via the bus system BS. N = 96 means that the respective data unit DE1-DEn has 96 data unit bits B1-B96. X = 4 means that the network formed by the bus system BS and the transceivers SE1-SE5 coupled via the bus system BS (see FIG 4 ), contains four subnets.

Step S3:

As indicated above, N check bits are stored at the corresponding data unit locations DP1-DP96 of another data frame DR8-DR11 to provide the test frame DR8-DR11 to the respective set M 'of data frames DR1-DR7 to be transmitted. To to example above 3 To return, it means that at the data unit position DP1 of the data frame DR8, the XOR operation XOR of the data unit bits B1 is stored at the data unit bit position DP1 of the data frames DR1 to DR7. Preferably, a single XOR operation XOR is performed for all data unit bits, eg B1, at the respective data unit bit position, eg DP1. In this case, the data frame DR8 forms the test frame DR8 for a first subnet, which is characterized in that the transceiver devices of this first subnet are to receive all provided data frames DR1 to DR7. Thus, for the first subnet M '= M = 7, so that the associated test frame DR8 must be formed over all data frames DR1-DR7. Consequently, all the data unit bits D1-D96 of the respective data unit to be backed up, for example, the data unit DE1 according to 3 are each XOR-linked at a predetermined data unit position DP1-DP96 to provide 96 check bits for the test frame DR8. Thus, the data unit bits B1 are logically XORed at the data unit position DP1 of all seven data frames DR1-DR7 to provide the first data unit bit B1 at the data unit bit position DP1 of the test frame DR8. The following data unit bits B2-B96 are analogous.

Process step S4:

The M data frames DR1-DR7 and the X test frames DR8-DR11 are transmitted via the bus system BS by means of a time-division multiplexing method. Preferably, a data frame DR1-DR11 in a slot SL1-SL11 predetermined by the time-division multiplexing method (see FIG 5 ) Posted.

The bus system BS is preferably designed as a flexray bus system with a flexray protocol which couples a predetermined number of transceivers SE1-SE5 (see FIG 4 ), wherein in each case one cycle or communication cycle of the time-division multiplexing method uses at least one static area in which at least one predetermined part of the transceivers SE1-SE5 is assigned at least one slot SL1-SL8 of identical length for transmitting data frames DR1-DR8, and at least has a dynamic range in which the respective slots SL9-SL11, each having a determinable length, can be dynamically assigned to at least a part of the transceivers SE1-SE5. Preferably, the X test frames DR8-DR11 are each initialized with a predetermined value, for example 0, before the beginning of a cycle of the time-division multiplexing process.

4 shows a schematic block diagram of an embodiment of the system for transmitting data frames DR8-DR11, each comprising at least one head segment KS and a data segment DS with at least one data unit to be secured DE1-DEn, which a predetermined data segment position DE1-DEn in the data segment DS and a having predetermined number N of data unit bits B1-B96 and having a checksum segment PS (see 2 ).

The inventive system has a bus system BS which has a predetermined number of Transceiver SE1 SE5 coupled. It points at least a transceiver SE1-SE5 has a first means, a second one Means, a third agent and a fourth agent. The first Means is suitable for sending a predetermined number N Provide data frame DR1-DR7. The second means is to suitable for one predetermined number X, with X ε [1, ..., N], one each bitwise XOR operation XOR the data unit bits B1-B96 each at a predetermined data unit position DP1-DP96 of a predetermined amount M ', with M' ≤ M, provided data frame DR1-DR7 to be sent for deployment of N check bits for one test frame DR8-DR11 to the respective amount M 'perform.

The third means is suitable for providing the N check bits respectively at the corresponding data unit positions DP1-DP96 of another data frame DR8-DR11 to provide the DR8-DR11 test framework to the respective one Quantity M 'provided to store data frame DR1-DR7 to be sent. Further, the fourth is Means suitable for this, the M data frames DR1-DR7 and the X test frames DR8-DR11 over to send the bus system BS by means of a time division multiplex method.

Preferably the bus system BS is designed as a Flexray bus system and the Transceivers SE1-SE5 each have a flexray communication control device on.

Preferably, the number X defines a number of subnets, wherein in each case one subnetwork has a predetermined number of transceivers SE1-SE5 coupled by means of the bus system BS, each of which contains the respective subnet M of the transmitted M data frames DR1-DR7 and the appropriate test frames associated with the respective subnet Receive DR8-DR11 from the respective predetermined transceiver SE1-SE5.

5 Fig. 12 shows a schematic flow diagram of one embodiment of a communication cycle or cycle in accordance with the present invention. The first line of the 5 shows a sequence of eleven slots SL1-SL11. The first transceiver SE1 transmits a data frame DR1-DR11 in each of the eleven slots SL1-SL11. The data frames DR1-DR7 are conventional data frames and the data frames DR8-DR11 are test frames. Since the number X of secure subnets is four, four test frames, namely the data frames DR8-DR11, are also necessary. Those data frames DR1-DR11 received by the respective receiving transceiver SE2-SE5 are, for the purpose of illustration in FIG 5 hatched marked.

Consequently receives the second transceiver SE2, the data frames DR1-DR7 and the test framework associated with the first subnet DR8. The third transceiver SE2 is receiving the data frames DR2, DR3, DR5 and DR6 and the second subnet associated test frame DR9. The fourth transceiver SE4 is receiving the data frames DR1, DR2 and DR5 to DR7 and the third Subnet belonging test frame DR10. The fifth transceiver SE5 receives the data frame DR2 and the test frame associated with the fourth subnet DR11. So M 'is for the first one Subnet seven, for the second subnet four, for that third subnet five and for the fourth subnet one.

6 shows a schematic, detailed representation of the according to 5 transmitting data frame DR1-DR11. A data frame DR1-DR11 consists of the data unit bits B1-B96, which are preferably imaged by the network management vector NMV defined in the flexray protocol 2.1, and the bits B97-B128 which are not to be protected.

at the eighth data frame DR8, which represents the test framework for the first subnet, become the data unit bits B1-B96 of the seven data frames DR1-DR7 each bitwise XOR-linked. In the ninth data frame DR8, which represents the test framework for the second subnet, are the data unit bits B1-B96 of the data frames DR2, DR3 and DR5, DR6 each XOR linked. In the tenth data frame DR10, which represents the test framework for the third subnet, become the data unit bits B1-B96 the data frames DR1, DR2 and DR5-DR7 are each XOR-linked. at the eleventh data frame DR11, which represents the test framework for the fourth subnet, becomes the data frame DR2, which is the only one for the fourth subnet to be transferred Represents data frame, retransmitted to provide redundancy.

Even though the present invention described above with reference to the preferred embodiments it is not limited to that, but in many ways and modifiable.

Claims (15)

Method for transmitting data frames (DR1-DR11), which in each case at least one head segment (KS) and a data segment (DS) with at least one data unit to be backed up (DE1-DEn), which contains a predetermined data segment position (P1-Pn) in the data segment (DS) and a predetermined number N of data unit bits (B1-B96), and a checksum segment (PS), with the steps: a) providing a predetermined Number of data frames to be sent (DR1-DR7); b) For a predetermined Number X, with X ε [1, ..., M], each bitwise XOR-linking (XOR) the data unit bits (61-B96) each at a predetermined data unit position (DP1-DP96) of a predetermined amount M ', with M' ≤ M, Provided data frame to be sent (DR1-DR7) for deployment of N check bits (B1-B96) for a test frame (DR8-DR11) to the respective quantity M c) respectively storing the N check bits (B1-B96) at the corresponding data unit positions (DP1-DP16) of another Data frame (DR8-DR11) to provide the test frame (DR8-DR11) to the respective quantity M 'provided, data frame to be sent (DR1-DR7); and d) sending the M data frames (DR1-DR7) and the X test frame (DR8-DR11) via a bus system (BS) by means of a time division multiplex method. The method of claim 1, wherein each of a data frame (DR1-DR11) in a time division multiplexed manner Slot (SL1-SL11) is sent. Method according to Claim 1 or 2, in which the bus system (BS) is a flexray bus system with a flexray protocol which couples a predetermined number of transceiver devices (SE1-SE5), wherein in each case one cycle of the time-division multiplexing method used is at least one static area in which at least one predetermined portion of the transceivers (SE1-SE5) is assigned at least one slot (SL1-SL8) of identical length for transmitting data frames (DR1-DR8), and optionally one or more dynamic areas has, in which the respective slots (SL9-SL11), each having a determinable length dynamically to at least one Part of the transmitting / receiving devices (SE1-SE5) can be assigned. The method of claim 3, wherein the M data frames (DR1-DR7) are sent in the static area. The method of claim 1 or one or more the claims 2 to 4, in which a display bit (A) is provided in the head segment (KS), wherein a positive logical value of the display bit (A) indicates that the data segment (DS) at least one data unit to be backed up (DE1-DEn) indicating a negative logical value of the display bit (A), the data segment (DS) has no data unit to be backed up. The method of claim 5, wherein the display bit (A) a payload preamble indicator which is according to the Flexray protocol in the header segment (KS) of a data frame (DR1-DR11) is. The method of claim 1 or one or more the claims 2 to 6, where the number X is a number of subnets of the bus system (BS), each subnet being a predetermined number from by the bus system (BS) coupled transceiver devices (SE1-SE5), which in each case the amount belonging to the respective subnet M 'the sent M data frame (DR1-DR8) and the corresponding to the respective Subnet associated Test frame (DR8-DR11) of a respective predetermined transmitting / receiving device (SE1-SE5) received. The method of claim 1 or one or more the claims 2 to 7, where a checksum (PS1-PS3) over at least a predetermined part of the data segment (DS) and / or of the head segment (KS) and the calculated checksum (PS1-PS3) in the checksum segment (PS) is stored. The method of claim 1 or one or more the claims 2 to 8, in which a defined in the Flexray protocol 2.1 Network Management Vector (NMV) which contains at least one data unit to be backed up (DE1-DEn). The method of claim 1 or one or more the claims 2 to 9, in which the additional test frame used to improve the detection probability of errors especially in such cases, where the CRC checksum is correct is even though the data frames are disturbed. The method of claim 3, wherein the X test frames (DR8-DR11) each before the beginning of a cycle of time division multiplexing be initialized with a predetermined value. System for transmission of data frames (DR1-DR11), each comprising at least one header segment (KS) and a data segment (DS) with at least one to be secured Data unit (DE1-DEn) which has a predetermined data segment position (P1-Pn) in the data segment (DS) and a predetermined number N of data unit bits and having a checksum segment (PS), With: a) a bus system (BS), which has a predetermined number of Transceiver Devices (SE1-SE5) coupled; b) wherein at least one transmitting / receiving device (SE1-SE5) has: b1) a first means, which a predetermined Provides number M of data frames to be sent (DR1-DR7); b2) a second means suitable for a predetermined number X, with X ε [1, ..., M] each have a bitwise XOR operation (XOR) the data unit bits (B1-B96) each at a predetermined data unit position (DP1-DP96) a predetermined amount M ', with M '≤ M, provided, Data frame to send Data frame (DR1-DR7) for deployment of N check bits for one test frame (DR8-DR11) to the to carry out respective amount M '; b3) a third means, which provides the N check bits respectively at the corresponding data unit positions (DP1-DP96) of another Data Frame (DR8-DR11) to provide the test framework (DR8-DR11) to the respective set M 'provided data frames to be transmitted (DR1-DR7) stores; and b4) a fourth means, which the M data frame (DR1-DR7) and the X test frames (DR8-DR11) via the Bus system (BS) using a time division multiplex method sends. The system of claim 12, wherein the number X of Subnets is provided, each subnet a predetermined Number of transceivers coupled by the bus system (BS) (SE1-SE5), which in each case the amount belonging to the respective subnet M 'the sent M data frame (DR1-DR7) and the corresponding test frames associated with the respective subnet (DR8-DR11) are received from the respective predetermined transceiver (SE1-SE5). System according to claim 12 or 13, wherein the bus system (BS) as a Flexray bus system is formed and the transmitting / receiving devices (SE1-SE5) respectively a Flexray communication control device. A system according to claim 1 or one or more the claims 13 or 14, where the additional test frame is used to improve the detection probability of errors, especially in such cases, where the CRC checksum is correct is, although the data frame is disturbed are.