Direct encapsulation of sensor data over Ethernet

Abstract

A sensor bridge (36) for use in an Ethernet network in a vehicle (24) includes a sensor interface (52), a mapper (56), and a communications processor (60). The sensor interface is configured to receive sensor data from sensors (28) installed in the vehicle. The mapper is configured to apply a direct mapping to the sensor data that maps designated portions of the sensor data to corresponding bit positions in one or more Ethernet packets to form mapped sensor data. The communications processor is configured to generate one or more Ethernet packets including the mapped sensor data and transmit the one or more Ethernet packets over the Ethernet network.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 313,291, filed February 24, 2022, the disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates generally to sensors and packet networks, and more particularly to methods and systems for transmitting sensor data over packet networks. [Background technology]

[0003] Various communication systems and applications, such as in-vehicle systems, involve the transmission of media such as audio and video over packet networks. One exemplary protocol for the transmission of audio and video over Ethernet networks is specified, for example, in IEEE Standard 1722-2016, December 2016, entitled "IEEE Standard for a Transport Protocol for Time-Sensitive Applications in Bridged Local Area Networks."

[0004] Various interfaces can be used to connect to sensors such as cameras and radars. An example of an interface between an image sensor and an application processor is the MIPI Camera Serial Interface 2 (CSI-2) interface, specified in "Errata01 for MIPI CSI-2 Specification (Camera Serial Interface 2) -Specification Version 2.1" of April 2018.

[0005] The above discussion is provided as a summary of the related art in the art and is not to be construed as an admission that any of the information it contains constitutes prior art to the present patent application. Summary of the Invention

[0006] The embodiments described herein provide a sensor bridge for use in an Ethernet network in a vehicle. The sensor bridge comprises a sensor interface, a mapper, and a communications processor. The sensor interface is configured to receive sensor data from sensors installed in the vehicle. The mapper is configured to apply a direct mapping to the sensor data that maps designated portions of the sensor data to corresponding bit positions in one or more Ethernet packets to form mapped sensor data. The communications processor is configured to generate one or more Ethernet packets including the mapped sensor data and transmit the one or more Ethernet packets over the Ethernet network.

[0007] In some embodiments, the mapper is further configured to add routing information to the mapped sensor data at the designated location for routing one or more Ethernet packets in the Ethernet network. Additionally or alternatively, the mapper is further configured to add Operations, Administration and Management (OAM) information to the mapped sensor data at the designated location for transmission in the one or more Ethernet packets.

[0008] In one embodiment, the mapper is configured to map the sensor data with a latency of not more than 1 microsecond. In a disclosed embodiment, the sensor bridge further comprises a memory buffer, and the mapper is configured to populate the memory buffer with the received sensor data according to a direct mapping and to output the mapped sensor data from the memory buffer.

[0009] According to embodiments described herein, there is additionally provided a method for transmitting sensor data in an Ethernet network in a vehicle. The method comprises receiving sensor data from a sensor installed in the vehicle. The mapped sensor data is formed by applying a direct mapping to the sensor data that maps designated portions of the sensor data to corresponding bit positions in one or more Ethernet packets. One or more Ethernet packets including the mapped sensor data are generated and transmitted over the Ethernet network.

[0010] The present disclosure will be more fully understood from the following detailed description of the embodiments thereof when considered in conjunction with the drawings, in which: [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram that generally illustrates an in-vehicle Ethernet communication system according to embodiments described herein.

[0012] [Diagram 2] 2 is a block diagram that illustrates a schematic of a mapper in a sensor bridge of the system of FIG. 1 according to an embodiment described herein.

[0013] [Diagram 3]1 is a flow chart that generally illustrates a method for direct mapping of sensor data into Ethernet frames, according to embodiments described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] In many applications involving the transmission of sensor data over packet networks, low latency is a major consideration. Consider, for example, an in-vehicle system that collects data from cameras, radar, lidar, and other sensors for analysis by a central processor. In such an environment, it is critical to analyze the data as quickly as possible, e.g., to identify safety hazards. Minimizing latency in such systems can have a direct impact on driver safety.

[0015] In current solutions, one of the main sources of latency is the latency caused by the interface between the sensor and the network, i.e., the process of receiving sensor data and converting it into communication packets. The embodiments described herein significantly reduce such latency using a direct mapping technique that directly maps sensor data into communication packets. The disclosed technique also reduces the size, cost, and power consumption of the hardware required to convert sensor data into communication packets.

[0016] The embodiments herein are described in the context of an Ethernet network in a vehicle, by way of example, but the disclosed techniques are not limited to any particular network type or protocol and may be used in any other network environment requiring low latency, such as in industrial control networks. The terms "packet" and "frame" are used interchangeably throughout this disclosure.

[0017] In some embodiments, the system includes a sensor bridge that connects a sensor to an Ethernet network. The sensor has a sensor interface, a mapper, and a communications processor. The sensor interface receives sensor data from the sensor. The mapper applies a predefined mapping that maps designated portions of the sensor data to respective bit positions in one or more Ethernet frames. The communications processor performs both Medium Access Control layer (MAC) and Physical Layer (PHY) functions to generate Ethernet frames that include the mapped sensor data. The Ethernet frames are transmitted over the network.

[0018] In some embodiments, the sensor interface receives sensor data, e.g., video data, radar data, lidar data, and / or audio data, in raw form from the sensors that is digitized by an analog-to-digital converter (ADC) coupled to the sensors. The sensor data is typically received over a high-speed parallel or serial bus.

[0019] The mapper uses a predefined mapping that maps designated portions of the sensor data to respective bit positions in one or more Ethernet frames. For example, in the case of a video camera, the sensor data includes video data and associated signaling. The mapping may specify bit positions in the Ethernet frames for signaling such as frame start, frame end, line start, line end, horizontal and vertical sync, for metadata such as timestamps, and for actual video pixel values. In this context, a mapping that maps designated portions of the sensor data to respective bit positions in one or more communication frames is referred to herein as a direct mapping.

[0020] In some embodiments, the mapping performed by the mapper is also direct in the sense that it requires only a single write operation to a memory buffer and a single read operation from the memory buffer. To enable direct mapping, in such implementations, the mapper has a memory buffer pre-configured according to the format of an Ethernet frame. The mapper populates the buffer with sensor data as it is streamed from the sensor interface by writing various portions of the sensor data to corresponding locations in the buffer as specified by the mapping.

[0021] By using the direct mapping techniques described herein, the latency of the sensor bridge (from when a particular bit of sensor data is received at the sensor interface to when that same bit is transmitted to the network in an Ethernet frame) can be significantly reduced. In some implementations, the mapper latency is typically reduced to 1 μs or less. The disclosed techniques also reduce the size, cost, and power consumption of the sensor bridge.

[0022] 1 is a block diagram that generally illustrates an in-vehicle Ethernet communication system 20 according to an embodiment described herein. In the embodiment described herein, the system 20 is installed in a vehicle 24 and includes a number of sensors 28 in communication with and controlled by a controller 32. The controller 32 is also referred to herein as a central processor or central computer. In other embodiments (not shown), the system 20 may be installed in an industrial network, a monitoring network, or other suitable network that involves transmitting sensor data over the network.

[0023] In various embodiments, the sensors 28 may include any suitable type of sensor, some non-limiting examples of sensors include video cameras, speed sensors, accelerometers, audio sensors, infrared sensors, radar sensors, lidar sensors, ultrasonic sensors, range finders or other proximity sensors, etc. The controller 32 may include any suitable type of processor, such as a CPU or GPU.

[0024] The sensors 28 and controller 32 communicate over an Ethernet network having multiple network links 40 and one or more Ethernet switches 44. The Ethernet links 40 may include, for example, twisted pair cables. The sensors 28 connect to the Ethernet network through one or more sensor bridges 36. A given sensor bridge may connect a single sensor or multiple sensors to the Ethernet network. The sensor bridges 36, switches 44, and controller 32 may communicate over the network links 40 at any suitable bit rate. Exemplary bit rates are 2.5 Gb / s, 5 Gb / s, or 10 Gb / s according to the IEEE 802.3ch-2020 standard, and 25 Gb / s according to the IEEE 802.3cy standard.

[0025] The inset on the left side of Figure 1 shows an exemplary implementation of sensor bridge 36 in one embodiment. In this example, sensor 28 outputs analog sensor data, e.g., analog video. Sensor 28 is coupled to an analog-to-digital converter (ADC) 48, which digitizes the analog sensor data and outputs the digitized sensor data.

[0026] The sensor bridge 36 includes a sensor interface 52 that receives digitized sensor data. The received sensor data includes various portions of different types, such as media (e.g., video pixel values ​​in the case of video, radar or lidar media in the case of radar or lidar, etc.), signaling (e.g., synchronization markers marking the start and end of lines and frames), metadata, operations, operations and maintenance (OAM) data, and / or any other suitable data type. The sensor interface 52 and the ADC 48 typically communicate over a 16-bit or 24-bit parallel bus.

[0027] The sensor bridge 36 further comprises a mapper 56 and a communications processor 60. The mapper 56 maps the sensor data directly into Ethernet frames using techniques described in more detail below. The mapper 56 creates MAC frames that are provided to the communications processor 60.

[0028] The communications processor 60 includes a MAC processor 64 that implements an Ethernet MAC layer, and a PHY processor 68 that implements an Ethernet PHY layer. The PHY processor 68 includes a Physical Coding Sublayer (PCS) module 72, a Physical Medium Attachment (PMA) module 76, and a Physical Medium Dependent (PMD) module 80 that implement the Ethernet PCS, PMA, and PMD sublayers, respectively. The resulting Ethernet frames are transmitted over suitable Ethernet links 40, for example to a switch 44.

[0029] In some embodiments, the sensor bridge 36 further comprises a routing information and OAM module 84 that inserts routing information and / or OAM data into the MAC frame. The routing information and / or OAM data may be added at any designated location in the MAC frame for the mapped sensor data. The routing information may include, for example, the source address (SA) and destination address (DA) of the Ethernet frame, a Virtual Local Area Network (VLAN) value to be assigned to the Ethernet frame, a priority (or other quality of service indication) for the Ethernet frame, the length of the Ethernet packet, and / or any other suitable parameters used in subsequent routing of the Ethernet frame through the network. The OAM information may include, for example, diagnostic data, control information for controlling a remote General-Purpose Input-Output (GPIO) port or control data read from a local GPIO port, control data and commands for remote register access, etc. Additionally or alternatively, in some embodiments, the sensor bridge 36 may insert information such as authentication data and / or encryption keys into the MAC frame.

[0030] In some embodiments, the routing information and OAM module 84 is locally and / or remotely programmable to generate and insert suitable information into the MAC frames. In one embodiment, the sensor bridge 36 includes a dedicated state machine that defines the timing of insertions, e.g., when to insert sensor data and when to insert routing and / or OEM information.

[0031] 2 is a schematic diagram of mapper 56 in sensor bridge 36 of system 20, according to an embodiment described herein. In this example, mapper 56 stores a direct mapping 88 that maps designated portions of sensor data to corresponding bit positions in one or more Ethernet frames. Mapper 56 has a memory buffer 92 organized according to mapping 88.

[0032] In some embodiments, buffer 92 has predefined memory locations (e.g., addresses) designated to store corresponding portions of the sensor data. In an embodiment, the designated memory locations in buffer 92 are ordered in the same order as the order of fields in a MAC frame that will be provided from mapper 56 to MAC processor 64 (see FIG. 1). In one embodiment, the format of the MAC frame, and thus the configuration of buffer 92, conforms to the IEEE 1722-2016 standard cited above.

[0033] The list of fields at the bottom of Figure 2 shows one non-limiting example mapping of this kind. In this example embodiment, the specified portion of the sensor data includes: Synchronization markers such as start of frame, end of frame, start of line, end of line, horizontal sync (H_SYNC), and vertical sync (V_SYNC). Embedded data such as a timestamp indicating when the sensor data was captured, the clock speed of the sensor interface, image parameters (e.g., resolution, refresh rate, pixel depth, color space), and register values. Media content according to sensor type (e.g. video data in a suitable format such as YUV, RGB or RAW, Inter-IC Sound (I 2 S), audio data in a suitable format such as lidar data, or radar data). Statistics calculated on the media content, e.g., video frame histograms. OAM information, such as diagnostic data, control information for controlling remote GPIO ports or control data read from local GPIO ports, control data and commands for remote register access, etc. User-defined data.

[0034] The above list is provided by way of example only: in alternative embodiments, mapping 88 may map any other suitable portion of the sensor data, and buffer 92 may be organized in any other suitable manner.

[0035] In a normal mode of operation, mapper 56 receives raw sensor data continuously and uninterruptedly from sensor interface 52 (FIG. 1). Mapper 56 analyzes the sensor data, identifies various portions of the sensor data, and populates buffer 92 accordingly.

[0036] In some embodiments, mapping 88 also maps the routing and / or OAM information provided by module 84 (FIG. 1) to corresponding bit positions within the Ethernet frame. As part of populating buffer 92, mapper 56 populates the appropriate positions within buffer 92 with the routing and / or OAM information.

[0037] In parallel with populating the buffer 92 with incoming sensor data, the mapper 88 streams MAC frames from the buffer 92 to the MAC processor 64 (FIG. 1). Using direct mapping in this manner, the end-to-end latency for the sensor bridge 36 (from when a particular bit of sensor data is received from the ADC 48 by the sensor interface 52 to when that same bit is transmitted from the sensor bridge 36 to the network in an Ethernet frame) is typically on the order of 1 μs.

[0038] 3 is a flow chart that generally illustrates a method for direct mapping of sensor data into Ethernet frames, in accordance with an embodiment described herein. In one embodiment, the method is performed by the sensor bridge 36.

[0039] The method begins with sensor interface 52 receiving raw digitized sensor data from ADC 48 at input operation 100. Mapper 56 maps designated portions of the sensor data (e.g., those portions enumerated in FIG. 2 above) to predefined bit positions in one or more Ethernet frames according to mapping 88 at mapping operation 104. Mapper 56 transmits the resulting MAC frames to communications processor 60.

[0040] At an Ethernet frame generation operation 108, the communications processor 60 generates one or more Ethernet frames that include the direct mapped sensor data. At a transmit operation 112, the communications processor 60 transmits the Ethernet frames over the link 40.

[0041] The configurations of the system 20, the sensor bridge 36, and the mapper 56 shown in Figures 1 and 2, and the method description of Figure 3, are exemplary configurations shown for clarity only. In alternative embodiments, any other suitable configurations may be used. Various elements of the system 20, the sensor bridge 36, and the mapper 56 may be implemented using dedicated hardware or firmware, such as using hardwired or programmable logic in an Application-Specific Integrated Circuit (ASIC) or a Field-Programmable Gate Array (FPGA). Additionally or alternatively, some functions of the system 20, the sensor bridge 36, and the mapper 56 may be implemented in software and / or using a combination of hardware and software elements. For clarity, elements that are not essential for understanding the disclosed techniques have been omitted from the figures.

[0042] In some embodiments, some functions of the system 20, the sensor bridge 36, and / or the mapper 56 may be implemented in one or more programmable processors, such as one or more Central Processing Units (CPUs), microcontrollers, and / or Digital Signal Processors (DSPs), programmed in software to perform the functions described herein. For example, the software may be in electronic form and downloaded over a network to any of the processors, or it may alternatively or additionally be provided and / or stored on a non-transitory tangible medium, such as a magnetic, optical, or electronic memory.

[0043] Although the embodiments described herein primarily address in-vehicle networks, the methods and systems described herein may also be used in other applications involving the transfer of video over a network, such as in security camera applications, industrial surveillance camera applications, and many others.

[0044] It should be noted that the above-described embodiments are cited as examples, and the present invention is not limited to what has been specifically shown and described above. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described above, as well as variations and modifications thereof not disclosed in the prior art that would occur to a person skilled in the art upon reading the above description. Documents incorporated by reference into this patent application shall be considered as an integral part of this application. However, to the extent that any term is defined in these incorporated documents in a manner that contradicts the definition expressly or impliedly made herein, only the definition in this specification shall be considered.

Claims

1. 1. A sensor bridge for use in an in-vehicle Ethernet network, comprising: a sensor interface configured to receive sensor data from a sensor installed in the vehicle; a mapper configured to apply a direct mapping to the sensor data to map designated portions of the sensor data to corresponding bit positions in one or more Ethernet packets to form mapped sensor data; and a communications processor configured to generate the one or more Ethernet packets having the mapped sensor data and transmit the one or more Ethernet packets over the Ethernet network. A sensor bridge comprising:

2. 2. The sensor bridge of claim 1, wherein the mapper is further configured to add routing information to the mapped sensor data at a specified location for routing the one or more Ethernet packets in the Ethernet network.

3. 2. The sensor bridge of claim 1, wherein the mapper is further configured to add operational, administration, and management (OAM) information to the mapped sensor data at a specified location for transmission in the one or more Ethernet packets.

4. A sensor bridge according to any preceding claim, wherein the mapper is configured to map the sensor data with a latency of not more than 1 microsecond.

5. 4. The sensor bridge of claim 1, further comprising a memory buffer, wherein the mapper is configured to populate the received sensor data into the memory buffer according to the direct mapping and to output the mapped sensor data from the memory buffer.

6. 1. A method for transmitting sensor data in an Ethernet network in a vehicle, comprising: receiving sensor data from a sensor installed in the vehicle; forming mapped sensor data by applying a direct mapping to the sensor data that maps designated portions of the sensor data to corresponding bit positions within one or more Ethernet packets; and generating the one or more Ethernet packets containing the mapped sensor data and transmitting the one or more Ethernet packets over the Ethernet network; A method comprising:

7. 7. The method of claim 6, wherein applying the direct mapping further comprises adding routing information to the mapped sensor data at specified locations for routing the one or more Ethernet packets within the Ethernet network.

8. 7. The method of claim 6, wherein applying the direct mapping further comprises adding operational, administration, and management (OAM) information to the mapped sensor data at designated locations for transmission in the one or more Ethernet packets.

9. The method of any one of claims 6 to 8, wherein applying the direct mapping comprises mapping the sensor data with a latency of not more than 1 microsecond.

10. 9. The method of claim 6, wherein applying the direct mapping comprises populating a memory buffer with the received sensor data according to the direct mapping, and outputting the mapped sensor data from the memory buffer.

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