Operation of a general-purpose data transmission system

Abstract

The present invention relates to a method for operating a generic data transmission system, in particular a method for operating a generic data transmission system designed for a vehicle architecture with certain limitations. The proposed method or data transmission system is designed to transmit data in a particularly hardware-efficient manner. This hardware efficiency is reflected, for example, in the fact that only one physical data channel is required and the corresponding components can be provided with low complexity. The present invention further relates to a data transmission system that performs the proposed method or a computer program product having control instructions for performing the method or for operating the data transmission system. Additionally, a computer-readable storage medium is proposed.

Description

[Technical Field]

[0001] The present invention relates to a method for operating a generic data transmission system, in particular a method for operating a generic data transmission system designed for a vehicle architecture with certain limitations. The proposed method or data transmission system is designed to transmit data in a particularly hardware-efficient manner. This hardware efficiency is reflected, for example, in the fact that only one physical data channel is required and the corresponding components can be provided with low complexity. The present invention further relates to a data transmission system that performs the proposed method or a computer program product having control instructions for performing the method or for operating the data transmission system. Additionally, a computer-readable storage medium is proposed. [Background technology]

[0002] The patent application WO 02 / 049994 describes a communication in a communication network, in particular a flexible deterministic communication network, and a method for use in a vehicle, for example an aircraft, spacecraft, ship or other vehicle.

[0003] Patent Document 2 shows a network interface device comprising a configuration engine, a mode change engine and a switch. Various video interfaces are known from the prior art, and these are typically optimized to transmit data over a computer network and then output it on a common end device. In this case, the prior art typically assumes that a high-performance computer system is available and that sufficient bandwidth is always available. Furthermore, such technologies do not take energy efficiency into account. In computer systems, energy efficiency is typically not a major concern, and only temperature rise and heat dissipation are considered. However, in automobiles, energy consumption directly reduces the driving range of electric vehicles.

[0004] Existing interfaces such as Displayport or HDMI® typically assume high bandwidth for the underlying data channel and are not optimized for latency.

[0005] Other conventional transmission systems rely on high-bandwidth data connections, transmitting data packets over long distances. The technologies used in today's Internet typically operate on a packet-based basis and use dynamic routing to cover large geographic distances. This requires multiple high-performance network nodes to find optimal data paths within vast computer networks at runtime. However, automobiles present completely different requirements, as the spatial scope is smaller and the data is often safety-related. Therefore, the high security and real-time requirements often make conventional technologies inapplicable. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] US Patent Application Publication No. 2017 / 0019479 [Patent Document 2] U.S. Patent No. 10,362,117 Summary of the Invention

[0007] Each of the example interfaces is optimized for a specific use (data type). Depending on the interface type, the interface provides one or more of the following, but not all at the same time: Low latency with unidirectional point-to-point or unidirectional multipoint connections for specific applications with up to 16 nodes (consumer video interfaces: DP / HDMI / DSI / CSI / LVDS), Low latency for bidirectional point-to-point or bidirectional multipoint connections (APIX2 / APIX3) with a fixed frame format (i.e., fixed allocated bandwidth) to meet latency requirements; High latency for highly flexible point-to-point and multipoint connections (Ethernet, TDM).

[0008] For the example interface, the following requirements cannot be met simultaneously: Lowest latency (possibly with prioritization), Dynamically allocated bandwidth (not fixed frame format), Two-way data stream, (Multi-Master) Multi-point data stream > 16 nodes, Bundling of all possible data types, · Making gateway functionality available across the network; Minimal protocol overhead.

[0009] Combining all of the above characteristics simultaneously would be desirable for a universal data transmission system for new vehicle architectures, as it would be able to accommodate both increasing complexity and bandwidth requirements, but this is currently not possible.

[0010] It is necessary to propose a method that allows efficient data transmission, regardless of the type of data, particularly in vehicle architectures. The proposed method should minimize the technical burden and transmit data via multiple network nodes regardless of the data format provided, thereby ensuring low complexity and low weight of these network nodes. It is also an object of the present invention to provide a data transmission system, a computer program product, and a computer-readable storage medium equipped accordingly.

[0011] This problem is solved by the features of claim 1. Further advantageous embodiments are set forth in the dependent claims. Therefore, a method for operating a generic data transmission system for a vehicle architecture is proposed, which method comprises dividing at least one physical data channel into a plurality of virtual data channels, reading user data (payload) in a transmitter of the data transmission system, and generating at least one data set according to a target data format. , describing user data Adding descriptive data to the user data and transmitting at least one data set from the transmitter to the receiver via a plurality of virtual data channels using static addressing. wherein the multiple data streams are bundled within a transport frame and transmitted serially. and receiving at least one data set at a receiver and retrieving user data for use therewith.

[0012] The data transmission system described below is able to simultaneously combine all of the above requirements in accordance with one aspect of the present invention. According to one aspect of the invention, the desired properties are achieved by: 128 virtual data paths with dynamic bandwidth allocation (based on prioritization) and bandwidth consumption only when data is being transferred; Two generic application adaptation units for burst and stream data that allow integrating all possible interfaces, a segmentation / reassembly unit for each send path and each receive path, which makes it possible to convert the application data into a standardized cell format; A service-independent peer-to-peer interface at the cell layer that provides low-latency repeater / routing functionality in all directions, which is necessary for the optional forwarding (routing) of individual virtual data paths; A crossbar unit for cell merging (TX path) or cell separation (RX path), Full-duplex configuration of each serial interface: All 128 virtual channels can operate in full-duplex mode if required. Option to create multiple serial interfaces for more bandwidth (x2, x3, x4). It is also possible to use an asymmetric structure, e.g., two TX-PHYs and only one RX-PHY (doubling the downstream bandwidth and leaving the upstream bandwidth unchanged).

[0013] This allows for the bundling of burst and stream data with minimal latency. Additionally, the bidirectional architecture allows for the bundling of multiple interfaces simultaneously, at any input and output point, and in any direction, through multiple functional units.

[0014] The proposed method for operating a data transmission system is based on the fact that the data transmission system is universal with respect to the user data (payload) transmitted. Therefore, according to the present invention, when data transmission is performed in any data format, the user data can be extracted and then repackaged and retransmitted, if necessary. Typically, data transmitted in a computer network contains surplus data, so-called overhead. This data can be, for example, frame data, header data, or footer data. While these are format-specific, the user data contains the actual information. Therefore, according to the present invention, a method is proposed for separating the overhead data from the user data, making it possible to accommodate any universal data format. This means that potentially any data format can be converted into another data format.

[0015] The proposed data transmission system comprises multiple network nodes connected by serial data channels, e.g., cables. The topology is static, i.e., no dynamic routing or addressing is performed, since the network topology is known in advance and can be omitted for efficiency.

[0016] In the proposed method, one physical data channel is operated that is subdivided into multiple virtual data channels. Preferably, one physical data channel is subdivided into 128 virtual channels. In general, it is also possible to provide multiple physical data channels, which are divided into multiple virtual data channels. It is also generally possible to provide a first number of physical data channels for a first communication direction and a second number of physical data channels for a second communication direction. Although methods for subdividing multiple physical data channels into multiple virtual data channels are generally known, the present invention proposes that the multiple virtual data channels are accessed independently of each other.

[0017] Thus, in accordance with the present invention, it is possible to operate multiple virtual data channels with different bandwidths and, implicitly, different latencies. Furthermore, individual data channels can be prioritized.

[0018] Furthermore, the user data (payload) is read in the transmitter of the data transmission system, and this reading can be performed so that the user data is read from a data source or from a transmitter that previously acted as a receiver and the user data is transmitted. Reading the user data can also include reading the user data from a data stream, whereby excess data, e.g., frame data, is also transmitted. Reading the user data corresponds to extracting the user data from a larger transmitted data set. How the user data is extracted from the data stream or multiple data packets can be determined according to the excess data. For example, the user data is transmitted in a specific data format, whereby the data format itself provides information on where to extract the user data from the entire transmitted data. Furthermore, reading the user data can also include further components, such as reading a measurement sensor or a data memory, e.g., a volatile data memory.

[0019] In a subsequent processing step, descriptive data is added to the user data in accordance with the target data format to create at least one data set. The descriptive data provides information about the content of the user data or describes the user data. While the user data describes the general raw data, the descriptive data exists to provide metadata somehow related to the user data. In this case, addressing data does not need to be present, since static addressing is performed in accordance with the present invention. The target data format can be specified by a network node of the data transmission system and determines which data formats the recipients of the descriptive data and user data can read. The target data format also clarifies which descriptive data should be added to the user data. The resulting data set corresponds to the target data format and optionally includes the descriptive data as well as the user data.

[0020] The at least one data set is then transmitted using the virtual data channel or the at least one data channel. When transmitting the at least one data set from the transmitter to the receiver, no addressing information or dynamic routing is used; instead, according to the present invention, static routing or static addressing is used. This is particularly advantageous for system architectures in motor vehicles, since all network nodes are known in advance or can be identified in an initialization step. The network nodes are hardwired, and therefore static addressing can also be applied. This has the advantage that the complexity of the individual network nodes can be minimized, resulting in error robustness and lighter weight.

[0021] Static addressing can be performed for each physical data channel or each virtual data channel. In this way, addressing information indicating the target network node can be specified. Generally, each network node can decide to which subsequent node it should send a data set, but this is always specified statically. It is not assumed to switch between multiple data paths within multiple network nodes. Therefore, addressing or routing is performed, but this is static and does not change during operation.

[0022] After the at least one data set has been transmitted, it is received by a receiver, which is also a network node of the data transmission system. The user data (payload) is then retrieved for use, which can mean that the user data is output by an output unit or that the user data is further processed. This further processing can include attaching description data to the retrieved user data again, the receiver taking on the role of a transmitter, and transmitting the attached user data to another receiver.

[0023] According to one aspect of the invention, the maximum number of virtual data channels per physical data channel is 128. This has the advantage that the proposed method can be implemented in a particularly advantageous manner to ensure that 128 virtual data channels ensure that sufficient bandwidth is available for each data channel and that an appropriate bit length is also available, which can be used in a particularly advantageous manner with regard to disparity. For example, it has been found that for a bit length of 128, 112 bits can be coded particularly efficiently, thereby supporting minimal overhead. The invention exploits this by creating multiple data channels of up to 128 bits per physical data channel.

[0024] According to a further aspect of the present invention, bandwidth is allocated separately for each virtual data channel. This has the advantage that multiple data channels can be configured differently depending on the application scenario, and therefore multiple individual data channels can also be prioritized by allocating higher bandwidth. Bandwidth can also be allocated dynamically during operation.

[0025] According to a further aspect of the invention, all virtual data channels operate at least temporarily in duplex mode. This has the advantage that operation in simplex mode is also possible, but that it is possible to switch at any time, or at least temporarily, to full-duplex mode. This means that multiple data channels, whether physical or virtual, can operate in bidirectional mode, so that data can be transmitted in both directions simultaneously.

[0026] According to a further aspect of the invention, there are different numbers of physical virtual data channels for each direction of communication. This has the advantage that in the case of directional data communication, the physical virtual data channels are also directional, but the directions do not have to be the same. This means that more data can be transmitted upstream or downstream, and the bandwidth of the corresponding communication direction can be increased accordingly. In other words, the transmission capacity required for a particular application scenario is provided in each case.

[0027] According to a further aspect of the invention, multiple virtual data channels are dedicated to continuous or discontinuous data sets (data records). This has the advantage that multiple separate interfaces or data channels are provided for either streaming data or burst data. In this way, particularly efficient structural features can be created, or the method can take advantage of these structural features. For example, the buffer memory can be configured to be larger for continuous data than for discontinuous data. The bandwidth for continuous data on the data channel can also be selected to be correspondingly larger.

[0028] According to a further aspect of the invention, multiple virtual data channels are prioritized independently of each other. This has the advantage that bandwidth can be dynamically configured on the fly or multiple data channels can be bundled. Furthermore, multiple latency times that must be met can be specified and multiple data channels are prioritized or configured accordingly.

[0029] According to a further aspect of the present invention, multiple network nodes of the data transmission system alternately operate as transmitters or receivers. This has the advantage that the network nodes can alternately assume the role of transmitter or receiver, thereby allowing different network topologies to be created. Thus, there can be multiple network nodes that represent only multiple data sources, i.e., multiple transmitters, or multiple network nodes that represent only multiple data sinks, i.e., multiple data receivers. In addition, there can be multiple addressing network nodes that function as both transmitters and receivers.

[0030] According to a further aspect of the invention, the user data is output via an output unit at the receiver and / or the receiver is a data sink. This has the advantage that individual network nodes can only receive data and output data, for example via a screen and / or a speaker, but do not generate their own data. Such network nodes may be referred to as data sinks.

[0031] According to a further aspect of the present invention, the method uses only volatile memory. This has the advantage that the network components or network nodes do not need to be designed in a complex manner, since data is not stored persistently. Volatile memory is typically faster and more efficient than persistent memory, which is particularly suitable for application scenarios in automobiles, which require simple components.

[0032] According to a further aspect of the invention, bidirectional routing is performed within multiple transmitters, which has the advantage that there are multiple individual network nodes that act as routers or addressing units, or even as so-called gateway routers.

[0033] According to a further aspect of the invention, the user data (payload) is (or is available as) video data and / or audio data. This method has the advantage that it is particularly suitable for a number of requirements in automobiles and also allows for the efficient transmission of large amounts of data. The invention can be implemented in a particularly advantageous manner using these data, since static addressing allows even large amounts of data to be transmitted efficiently and without long latency times. Therefore, since video data and audio data must always be transmitted continuously, these real-time applications can be transmitted in a particularly advantageous manner using this method.

[0034] One aspect of the present invention is to bundle multiple data streams (video, audio, and data) into a single transport frame and transmit the multiple data streams serially. Different data formats not only have different bandwidth requirements, but also different latency, reassembly sublayer, and bit error rate requirements. In particular, the transmission of today's video data formats requires not only the transmission of pure video data and its frame information, but also the support of encryption methods such as HDCP. All of this requires many different data channels with a wide range of bandwidth, latency, and reassembly sublayer requirements. Additionally, this requires a network architecture that is much more complex than a simple transmitter / receiver architecture can provide. An architecture with multiple repeaters where data paths can originate and terminate, allowing data paths to branch (Y-shaped), and recombine multiple data paths into a single link would be advantageous.

[0035] According to one aspect of the present invention, the technology follows the basic idea of ​​bundling different services, but offers completely new possibilities in terms of network architecture and enables new approaches in the implementation of today's video interfaces. In addition, the technology can be used as a universal data transport layer, for example to transmit Ethernet data or camera data or any kind of sensor data.

[0036] In a virtual path, all packets / cells follow the same path, as opposed to IP, where a packet may reach its destination by a different path than the packets before and after it, so latency and reassembly sublayers are constant across a virtual path.

[0037] Multiple virtual paths have the advantage that they can be used as a multiplexing layer for different services (video, audio, Ethernet), since the characteristics of the different virtual paths can be configured differently without the different virtual paths interfering with each other.

[0038] Multiple virtual paths consume bandwidth only when data is actually being transferred. The multiple virtual path concept also makes it possible to implement a wide range of complex diagnostic and network configuration functions at run time using multiple separate (virtual) data channels.

[0039] According to one aspect of the present invention, a virtual path layer is implemented between the physical layer (serializer and framer) and the various application data interfaces.

[0040] In accordance with one aspect of the present invention, this virtual path layer is used to multiplex several different data paths and to support more complex architectures with repeaters and branches, which is primarily done at the cell layer.

[0041] According to one aspect of the invention, a further part of the virtual path layer is an application adaptation layer that performs the conversion of video (stream) or e.g. Ethernet (packet) data into cells, and also includes a number of OAM functions for network diagnostics and management.

[0042] In accordance with one aspect of the present invention, the present technology can be the basis for transmitting various data formats over serial connections in automobiles (and elsewhere), thus forming the basis for a new generation of devices.

[0043] The high serial bandwidth requires the definition of architectures, cell formats and interfaces that allow flexible internal data bus widths in order to match the speed of the internal clock system to the capabilities of the chip technology.

[0044] According to one aspect of the present invention, the virtual path layer includes a physical layer including a transmission sublayer and a physical media sublayer, a cell layer, and an application adaptation layer including a plurality of segmentation and reassembly sublayers and including a plurality of functions for adapting a plurality of data formats to corresponding applications.

[0045] The primary role of the physical layer is to establish a physical connection to another physical layer. This connection is essentially bidirectional. In theory, this connection can be realized over a wide variety of media. In practice, two serial differential Gbps connections are used. This layer is responsible for line coding, inserting empty cells to decouple the cell rate from the connection rate, and assembling the cell stream into a serial frame.

[0046] In the cell layer, the segmented data (cell payload data) of the segmentation and reassembly sub-layer is assembled into a complete cell with a header, VP identifier, and CRC, or the cell is CRC checked and the payload is passed to the segmentation and reassembly sub-layer, which also multiplexes different cell streams for multiple application adaptation (customization) functions, or distributes cell payloads to application adaptation functions according to the VP identifier (feed-in / feed-out).

[0047] According to one aspect of the invention, the cell layer also provides for the multiplexing and demultiplexing (transportation) of cell streams in repeaters and splitters. According to one aspect of the invention, the role of the application adaptation functions is to adapt the data of the application interface to the format of the user data (payload) field of the cell and to send control information to the other side or to send control information to the other side to be used in the adaptation process (time generation, framing).

[0048] According to one aspect of the present invention, all virtual data paths are unidirectional, i.e., they start at an initiator and terminate at one or more targets. If multiple virtual data paths are logically related to form a bidirectional data path, such as in HDCP for a video channel, then these paths should have the same VP identifier.

[0049] A virtual data path begins at an initiator and terminates at one or more targets. The virtual data path is realized by the Cell sublayer, which performs the following functions on the virtual path: Add / remove multiplexing, ·VP conversion.

[0050] The object can also be achieved by a data transmission system for a vehicle architecture, the data transmission system comprising a fragmentation unit configured to fragment at least one physical data channel into a plurality of virtual data channels, an interface unit configured to read user data (payload) in a transmitter of the data transmission system, and an interface unit configured to read user data (payload) in accordance with a target data format to create at least one data set. , describing the payload data a packaging unit configured to add descriptive data to the user data; and a transmitting interface unit configured to transmit at least one data set from a transmitter to a receiver via a plurality of virtual data channels using static addressing. a transmitting interface unit, wherein the plurality of data streams are bundled within a transport frame and transmitted serially;and a receiving interface unit configured to receive at least one data set at the receiver and to retrieve user data for use therewith.

[0051] The problem is also solved by a computer program product with control instructions for implementing the proposed method or for operating the proposed apparatus. According to the invention, it is particularly advantageous if the method is used to operate the proposed devices and units. Furthermore, the proposed devices and units are suitable for implementing the methods according to the invention. Thus, in each case, the devices comprise a number of structural features suitable for carrying out the corresponding methods. However, these structural features can also be configured as process steps. The proposed methods also provide a number of steps for realizing the functions of the structural features. In addition, the physical components can also be virtually provided or virtualized.

[0052] Further advantages, features, and details of the present invention will become apparent from the following description in which aspects of the invention are described in detail with reference to the drawings. The features described in the claims and the specification may each be important to the present invention individually or in any combination. Similarly, the features described above and further described herein may be used individually or in any combination. Functionally similar or identical parts or components are designated by the same reference numerals. The terms "left," "right," "top," and "bottom" used in the description of the embodiments refer to normally readable figure designations or drawings bearing normally readable reference numerals. The illustrated and described embodiments should not be construed as definitive but are exemplary in nature for purposes of describing the present invention. The detailed description is intended to provide information to those skilled in the art; therefore, known circuits, structures, and methods are not shown or described in detail in the description so as not to obscure an understanding of the description. [Brief explanation of the drawings]

[0053] [Figure 1] FIG. 1 is a schematic flow chart of a method for operating a general-purpose data transmission system according to one embodiment of the present invention. [Figure 2] FIG. 2 is an exemplary network based on a defined number of functional units of the proposed system architecture according to a further aspect of the present invention. [Figure 3] FIG. 3 is a proposed data transmission system according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0054] Some of these figures contain parameters that are well known to those skilled in the art in English notation and are used as parameters and should not be translated. FIG. 1 shows a schematic flow chart of a method for operating a generic data transfer system for a vehicle architecture, the method comprising: dividing (100) at least one physical data channel into a plurality of virtual data channels; reading (101) user data in a transmitter of the data transmission system according to a target data format to create at least one data set. , describing user data Adding descriptive data to the user data (102) and transmitting at least one data set from the transmitter to the receiver via the virtual data channel using static addressing (103). wherein the plurality of data streams are bundled within a transport frame and transmitted serially (103). and receiving at least one data set at a receiver and retrieving user data for use therewith (104).

[0055] Figure 2 shows different network nodes of the proposed data transmission configuration or system. The network nodes can function as transmitters, receivers, and can also function as data sources or data sinks. In addition, the left-hand components show inputs and outputs for streaming data (i.e., continuous data) and burst data (i.e., discontinuous data). Also shown is the communication direction, which can be dual simplex or bidirectional. The illustrated network nodes can be combined as illustrated in Figure 3, but can also be used in different configurations or topologies to create the proposed data transmission system.

[0056] Therefore, in simple terms, we can define a functional family consisting of three functional units, which can be described as follows: 1. A pure gateway (G) (also known as a transceiver) that can package / unpack stream data and / or burst data; 2. A pure router (R) or m × n crossbar (m, n ∈ N) that can route data in any direction; 3. m×n gateway routers (G / R) (m, n∈N) that can package / unpackage stream and / or burst data and route data in any direction.

[0057] Any other combinations are possible based on the concepts described above. The functional units shown are intended to give an idea of ​​the flexibility of the architecture. Figure 3 shows a proposed data transmission arrangement or system operating according to the proposed method. Several components of Figure 2 are used here in a particularly advantageous manner. This data transmission system is used in a motor vehicle.

[0058] CPU1 and CPU2 can communicate bidirectionally via PCI Express through their respective 1x2 gateway routers (1) and (2), and can also bidirectionally access gateway (3) via PCI Express. At the same time, CPU1 can provide video data to 1x2 gateway router (1) via HDMI and DisplayPort, which can then be output again to gateway (4) as DSI and again to gateway (7) as eDisplayPort. Additionally, CPU2 can operate gateways (4) and (6) and router (5) using the bidirectional MII interface on 1x2 gateway router (2). Router (5) exhibits an unused serial interface that can be used, for example, for later network expansion.

[0059] The depicted network should be understood as an example configuration: networks of any complexity with any conceivable application interface in any direction are contemplated.

[0060] The gateways, routers, and gateway-routers presented herein enable completely new network and data architectures within vehicles, because there is a standardized transport layer that can route and bundle all existing interfaces in any direction to any gateway / router / gateway-router, while optimally utilizing bandwidth and meeting the lowest latency requirements, and because it is possible to perform "interface bridging" where necessary (DisplayPort input in one gateway to DSI output in another gateway for the same data type, e.g., video data type).

[0061] Furthermore, bundling can reduce in-vehicle plug connections, cables, weight, power, and ultimately cost. Such a bundled network is likely to be less prone to errors than many individual point-to-point connections. Additionally, error diagnosis in a network such as the one presented may also be greatly simplified by bundling.

[0062] The network shown in this configuration can be easily expanded by using routers / gateway routers to provide new possibilities for, for example, model updates and equipment options.

[0063] Physical Media Sublayer Purpose and Function The lowest layer of the physical medium is electrically connected to the physical transmission medium. The primary transmission medium is differential 100 ohm wiring, although optical transmission media are also an option.

[0064] The physical transmission format depends on the data rate and is NRZ for low data rates and PAM4 for high data rates. This layer performs serialization of M-bit parallel line-coded data (M=raw serializer bit width) on the sending side, and performs recovery of the serial clock and bit-serial data on the receiving side and deserialization into M-bit-parallel line-coded words. The serial data transmission is based on the "Embedded Clock" concept, i.e. no time information is transmitted, only serial data, which allows for clock recovery by line coding.

[0065] The core clock frequency is mainly determined by the SERDES "Raw Bit Width" M. For example, for 30 Gbps and a raw bit width M=128, the core clock frequency is 234.375 MHz.

[0066] Interface to Physical Media In the transmission media direction, the physical media sublayer according to one aspect of the present invention implements two unidirectional, differential, bit-serial 100-ohm interfaces (transmit and receive interfaces). The physical media has differential forward and return lines throughout. This configuration allows for arbitrary operation of the optical media without major adaptation circuitry.

[0067] The focus is on twisted pair cable as the physical medium because at high frequencies the insertion loss of coaxial cable is equal to that of twisted pair cable. Considering that single-ended transmission has a 6 dB attenuation compared to differential transmission, coaxial cable remains without any advantage.

[0068] The maximum cable length depends on the data rate (and cable diameter). According to one aspect of the invention, a bit time system (Bitzeitsystem) for serializing data is generated in the transmit direction using a PLL. Data / symbols are transmitted in this bit time. This bit time forms the basis of a synchronous Tx clock system. The Tx data path is directed in the opposite direction to this time system (target synchronization).

[0069] In the receive direction, the time used to serialize the data is recovered from the received serial data stream using a CDR. This time forms the basis of a synchronous Rx clock system. The Rx data path is oriented in the same direction as this time system (the synchronization source (Quelle synchron)).

[0070] It is said that the core clock frequency is mainly determined by the SERDES "raw bit width" M. For example, for 30 Gbps and a raw bit width M = 128, the core clock frequency is 234.375 MHz. As SERDES technology can change, M also changes. Therefore, the cell format and cell data interface between different layers must support flexible SERDES raw bit widths or decouple the cell format from the cell line data width.

[0071] Transmission sublayer Purpose and Function According to one aspect of the present invention, in the transmit direction, the transmit sublayer generates M-bit wide line code symbols for the SERDES RAW interface (SERDES-Rohschnittstelle) from N-bit wide transmit frames (see 7. Transmission Frame and Cell Format for details), and in the receive direction, it again generates N-bit wide transmit frames from the M-bit symbols of the SERDES RAW interface.

[0072] The main function of the transmit sublayer is to assemble transmission frames from cells in the transmit direction and, conversely, to disassemble transmission frames into cells in the receive direction. To adapt the data rate of the cell stream to the data rate of the serial transmission, this layer can insert empty cells in the transmit direction (from the application interface to the serializer) according to one aspect of the present invention. The availability of cells depends on the total bandwidth requirement of all application interfaces. Therefore, according to one aspect of the present invention, multiple cells do not form a continuous flow of cells, since they are processed (collected, assembled, and combined) using a core clock that limits the maximum bandwidth of the SERDES.

[0073] In the receive direction (from the deserializer to the application interface), empty cells are discarded. Cells are extracted from the serial frame. As in the transmit direction, these cells are forwarded with a data valid signal because the cell data rate is lower than the bandwidth for core time.

[0074] This layer processes the flow of cells: in addition to generating the cell header and CRC or extracting the data from the cell by CRC checking, the so-called add-drop multiplexer function is implemented.

[0075] This means that in the transmit direction, multiple cells are collected by various service functions, assigned VP identifiers, cell headers and footers are generated and collected by the peer-to-peer interface, and then multiplexed into a common cell stream (additional functions).

[0076] In the receive direction, according to one aspect of the invention, the cell stream is distributed from the input device in the receive direction to the various service functions and peer-to-peer interfaces according to the VP identifier. Data destined for the service function is unpacked and CRC checked (drop function). All cells whose VP identifier does not belong to the service function are forwarded to the peer-to-peer interface (forward function).

[0077] One or more Application Adaptation Layers (AALs) The Application Adaptation sublayer is the "top" layer in the three-layer model. Here, cell-based virtual data paths are translated back to physical data paths. These are connected to various application interfaces via a generic service interface for stream or burst data.

[0078] The rules for dividing and reassembling packets and streams into cells are called the application adaptation sublayer. The two most important ones are stream data, e.g., video and audio data, and burst data, e.g., packets of almost any kind. Which AAL is used in each case is not coded in the cell; instead, it is determined on the basis of the virtual connection, or connection, established between the two endpoints.

[0079] Segmentation & Re-Assembly Sublayer (with AAL functionality) Purpose and Function In the transmit direction, a segmentation layer according to one aspect of the present invention, together with application-specific AAL functions, forms the starting point of a cell-based virtual data path.

[0080] In the receive direction, a reassembly layer, together with application-specific AAL functions, forms the termination point for cell-based virtual data paths.

[0081] The main role of the segmentation and reassembly sublayer (together with application specific AAL functions) is to enable format conversion (bit width) of streaming or burst data of any bit width into the N-bit wide cell line data format.

[0082] The interface between the stream data or burst data function and the segmentation and reassembly sublayer has a bit width of cell lines (N). The stream data or burst data AAL function combines clock domain crossing and bit width conversion of data from the application interface to the N bits of the cell lines. The payload of a cell line is already formatted so that the cell footer and cell header fit into the first and last cell lines, respectively.

[0083] The segmentation and reassembly sublayer essentially controls the data flow through the AAL function, which assesses the availability of application data and (if necessary) the acceptance of cell data (backpressure to be defined).

[0084] According to one aspect of the present invention, the cells provide the capability to transmit payload information data in addition to payload data (see 7.1 Cell Format), which may be used to generate, for example, video or audio frame signals in the case of stream data, or packets, transactions, and bursts in the case of burst data.

[0085] Binding of multiple frame signals to stream data using payload information The basic idea behind binding multiple frame signals to a data stream is to define a key anchor point (or anchor points) in the frame timing (frame time) and transmit this (or these) using payload information bits to enable unambiguous synchronization of the data stream and the multiple frame signals. Ideally, this is done by placing a fixed point in the data stream at a fixed point within a marked data cell. To recover the frame timing, a free-running timing generator is used, which can generate the entire timing independently. The timing is then adapted to the data stream by analyzing the payload information bits and adapting them to the defined positions within the data cells.

[0086] Stream data (continuous data stream) The stream data interface combines the switching from the application clock domain to the cell clock domain and the bit-width conversion of data from the application interface to the N bits of the cell row, whose payload is already pre-formatted so that the cell footer and cell header fit into the first and last cell row.

[0087] Streaming data is (usually) synchronized to the source, where clock domain crossing of the data path from the application clock domain to the cell clock domain is performed.

[0088] A data buffer is provided in the transmit direction, into which source synchronous data is written by the application clock. An input device in the transmit direction retrieves data from this buffer as needed and performs data format conversion into N-bit wide cell rows. Frame signals (e.g., Hsync, Vsync, DE) are encoded into payload information bits so that the frame signals can be reconstructed at the receiver side.

[0089] In the receive direction, the cell data is written into a data buffer by an output device in the receive direction. The frame signal is reconstructed based on the payload information bits. The transmit application clock is regenerated, for example, using the buffer fill level and clock synthesis.

[0090] If data encryption is required (HDCP), this function encrypts or decrypts the cell data. Since there are different types of stream data, such as audio and video, including encrypted and unencrypted types, different implementations of the basic functions may exist (for example, VStream In / Out, AStream In / Out, EncVStream In / Out).

[0091] Burst data (discontinuous data streams) The burst data interface combines switching from the application clock domain to the cell clock domain and bit-width conversion of burst data from the application interface to N bits of cell rows, whose payloads are already pre-formatted so that the cell footer and cell header fit into the first and last cell rows.

[0092] The burst data is (usually) synchronized to an external clock and has different identification signals for direction and data type (address / data / byte enable). This data is usually accompanied by control lines in order to implement a particular protocol.

[0093] A data buffer is provided in the transmit direction, and burst data is written into the data buffer by the interface clock. An input device in the transmit direction retrieves data from the buffer as needed and performs data format conversion into N-bit wide cell rows.

[0094] In the receive direction, cell data from the output device is written into a data buffer in the receive direction, and interface control signals are reconstructed based on the payload information bits. The payload information bits are used to generate control signals for the application specific interface or to synchronize protocol state machines in the application specific interface.

[0095] Because there are different interfaces that provide burst-like data (SPI, I2C, MII), there can be different implementations of the basic functionality (e.g., SPIBurst, I2CBurst, MIIBurst).

[0096] Therefore, there will be (slightly) different stream in / out interfaces, but their structure will be the same. Cell format / frame format According to one aspect of the present invention, a cell includes a header having a fixed bit length, a payload area having four selectable bit lengths, and a footer having a fixed bit length.

[0097] The cell structure is a sequence of bits as follows: A 7-bit virtual path (VP) identifier that represents the unique address of the virtual path, A 3-bit sequence number (SN) that consecutively numbers multiple cells in their order (sequence), A 2-bit wide cell type (CT) identifier that specifies the length of the payload (user data), A 3-bit wide payload information (PI) containing additional information about the payload. This is also used to synchronize the payload data with the frame data or control data. A 10-bit wide CRC polynomial (HCRC) for error protection of header information. This polynomial has a Hamming distance of 5 up to a 21-bit bit sequence (P=0x2B9). The payload (PL) area has a length of 187, 411, 635, or 859 bits depending on the CT value. The shortest payload is chosen to be larger than the bus width of the largest supported (video) streaming. This simplifies the mapping of streaming data into the payload of a cell. Finally, a 12-bit wide CRC polynomial (PCRC) for error protection of the user data (payload data). This polynomial has a Hamming distance of 4 up to a 2035-bit bit sequence (P=0x8F3).

[0098] Transmission frame format According to one aspect of the invention, a transmission frame includes a sequence of M-bit wide words. The frame starts with an M-bit wide "comma" word from a sequence of comma words defined for frame alignment. This is followed by K cells. A cell consists of 2, 4, 6 or 8 N-bit wide words that carry a header, payload and footer. These N-bit wide words are coded into M-bit wide symbols (line coding).

[0099] This format is chosen to allow the cell data to be processed at the appropriate time frequency, provided that the serializer / deserializer always processes blocks of M bits.

Claims

1. 1. A method for operating a universal data transmission system for a vehicle architecture, comprising: Dividing (100) at least one physical data channel into a plurality of virtual data channels; Reading (101) user data at a transmitter of said data transmission system; adding (102) descriptive data to the payload data according to a target data format to create at least one data set; transmitting (103) the at least one data set from the transmitter to a receiver over the plurality of virtual data channels using static addressing; receiving (104) the at least one data set at the receiver and retrieving the user data for use therewith.

2. 2. The method of claim 1, wherein the maximum number of virtual data channels per physical data channel is 128.

3. 3. A method according to claim 1 or 2, characterized in that for each virtual data channel, the bandwidth is allocated separately.

4. 4. A method according to claim 1, wherein all virtual data channels operate at least temporarily in duplex mode.

5. 5. A method according to any one of claims 1 to 4, characterized in that there are different numbers of physical and / or virtual data channels for each communication direction.

6. 6. A method according to any one of claims 1 to 5, wherein the plurality of virtual data channels are dedicated to contiguous or discontiguous data sets.

7. 7. A method according to any one of claims 1 to 6, wherein the virtual data channels are prioritized independently of each other.

8. 8. The method according to any one of claims 1 to 7, characterized in that a plurality of network nodes of the data transmission system act alternately as transmitters or receivers.

9. The method according to any one of claims 1 to 8, characterized in that the user data is output at the receiver via an output unit and / or the receiver is a data sink.

10. 10. The method according to any one of claims 1 to 9, characterized in that only volatile memories are used.

11. 11. A method according to any one of claims 1 to 10, characterized in that bidirectional routing is performed in a plurality of transmitters.

12. The method according to any one of claims 1 to 11, wherein said user data is at least one of video data and audio data.

13. 1. A data transmission system for a vehicle architecture, comprising: a fragmentation unit configured to fragment (100) at least one physical data channel into a plurality of virtual data channels; an interface unit configured to read (101) user data in a transmitter of said data transmission system; a packaging unit configured to add (102) descriptive data to said payload data according to a target data format to create at least one data set; a transmitting interface unit configured to transmit (103) the at least one data set over the plurality of virtual data channels from the transmitter to a receiver using static addressing; a receiving interface unit configured to receive the at least one data set at the receiver and to retrieve (104) the user data for use therewith.

14. 13. A computer program product comprising instructions which, when said program is executed by at least one computer, cause said computer to perform the steps of the method of any one of claims 1 to 12.

15. A computer readable storage medium containing instructions which, when executed by at least one computer, cause the computer to perform the steps of the method of any one of claims 1 to 12.

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