"The latest on-board 5g communication test results show that when the vehicle speed is 100km / h, the data transmission rate can reach 8gbps. In other words, you just stepped on the accelerator and a HD movie has been downloaded into your car.
However, when you download cloud data to the car at a fast speed and try to transmit these things to various parts of the car again, a disaster occurs. The bottleneck is the transmission rate of CAN bus.
It has been 30 years since BMW first used can bus in the car in 1988. At present, the theoretical limit transmission speed of the latest can FD standard is 1Mbps, that is, it takes 24 seconds to transmit a 3M size picture. If the firmware of one of your core controls is relatively large, it may take several hours for you to transmit the software through the CAN bus.
This is the information transmission capability of the internal nerves and blood vessels of the automobile. This is an internal communication transmission architecture designed for the mechanical age.
For a long time, automobile has been regarded as the product of traditional industry, and network communication is an emerging force originated in Silicon Valley; Now, the two worlds are embracing each other, and the deep integration is irreversible. As an analogy, the new energy power system replaces the heart of the car. Driverless transformation is the brain of the car. The Internet of cars changes the perception mode of the car by reshaping the five senses. It is only the last step from a whole-body operation to build a new nervous and vascular system, which is the car Ethernet.
Current situation of automobile harness
Before the concept of automotive Ethernet appeared, there were many different bus standards in automotive applications, including can, Lin, FlexRay, most and LVDS. Almost every part of the automotive electronic system has its own specific cable and communication requirements, which leads to complex wiring and redundant standards in the vehicle. In terms of weight, the wiring harness in the vehicle occupies the third place after the chassis and engine; At the same time, the wiring harness in the vehicle has also become the third largest part of the cost in the vehicle after the engine and chassis. Regardless of the production process or maintenance process, the labor cost of wiring accounts for 50% of the whole vehicle, and these jobs can not be replaced by machinery unless the bionic robot makes a breakthrough. It has been said that the civilization of a city is related to its sewers. No matter how modern a city is, it also needs sewer workers to maintain it; Similarly, a luxury car, no matter how bright it looks, also needs workers' fine wiring work.
(line speed deployment in Audi A5)
Elon Musk once said: on model s, the length of the whole vehicle harness is 3km; On Model 3, the data is about 1.5km. On the model y to be launched in the future, the harness length will be further shortened to only 100 meters“ Sell 100000 vehicles a year, and the cables can circle the earth. Does it surprise your chin? Even Tesla, a high-tech car company, also cut the harness. I can't help it. For vehicle R & D and manufacturing, the detail of harness is a little unusual. Insanity is not fun!
Statistics show that the cost of a low-end vehicle harness system is about 300 US dollars, the weight is about 30 kg, the length is about 1500 meters, about 600 harnesses and 1200 contacts; The harness system of a luxury car costs about 550-650 dollars, weighs about 60 kg, has about 1500 harnesses, a length of about 5000 meters and 3000 contacts. If the current electronic architecture system is used, the harness cost in the era of unmanned vehicle will not be less than 1000 US dollars and the weight can reach 100 kg“ This is the current situation of the harness, and there is an urgent need for a unified standard and simplified scheme.
Limitations of traditional automobile harness
Can bus originated in the 1990s and is mainly used for on-board control data transmission. It is the most widely used standard of on-board network in service, with a maximum transmission speed of 1 MB / s.
Lin is a low-cost universal serial bus, which is mainly used for door, sunroof and seat control in the automotive field. The maximum transmission speed is lower, only 20 KB / s.
The main advantage of FlexRay is that compared with CAN bus, it has higher bandwidth, up to 10MB / s, which can meet the requirements of key automotive applications, but its cost is very high. It is mainly suitable for wire control systems in medium and high-end vehicles (such as suspension control, transmission control, brake control, steering control, etc.).
Most mainly supports multimedia streaming data transmission. The maximum bandwidth of most150 standard is 150 MB / s, which is widely used in on-board multimedia data transmission. Although most150 supports IP based applications, the basic development cost is high due to the problem of a single vendor.
LVDS is an electrical digital signal system, which transmits high-speed data (up to 850 MB / s and the longest transmission distance of 10 m) through copper twisted pair. It is originally a part of network communication bus. In the automotive field, LVDS is mainly used for data transmission between screen and camera.
The traditional automobile bus can meet the requirements of some subsystems. Generally speaking, the advantage is real-time. But the common problem is low bandwidth and high cost. Basically, these bus standards are formulated for automobiles, with a strong color of the automobile industry. The key limitation is that they are not easy to expand and cannot be interconnected. In the era of Internet of vehicles and driverless, these traditional buses are like aging hemangiomas, blocking the channel extending from informatization to the interior of vehicles.
Ethernet communication
Ethernet technology was invented in 1973. After more than 40 years of development, it has been the most widely used LAN technology, and even can be applied to WAN. Strictly speaking, Ethernet does not specifically refer to a bus technology. It is a series of standard protocols under IEEE 803.2 working group. Ethernet initially supported 10mbit / s throughput. After continuous development, there are fast Ethernet (100mbit / s), Gigabit Ethernet (1GBIT / s), 10Gbit Ethernet (10Gbit / s) and 100Gbit / s. At the same time, in order to adapt to the diversity of applications, the Ethernet rate broke the Convention of increasing by 10 times and began to support the rates of 2.5, 5, 25 and 400gbit / s. The transmission medium can be not only twisted pair copper wire, but also optical fiber.
Advantages of Ethernet
It can be seen that Ethernet can not only support higher bandwidth throughput, but also has relatively low cost. In addition, the unshielded single pair twisted pair of broadr reach does not need aluminum foil layer and insulating adhesive layer. This cable is lighter than the traditional network cable, and its anti electromagnetic radiation performance is also excellent, and has passed the ISO-9001 and TS16949 standards. In terms of security, Ethernet can transplant mature applications in the field of network communication to build its own secure LAN, such as data encryption, firewall, deep packet detection (DPI), etc.
(traditional network cable on the left and vehicle Ethernet cable on the right)
The key is that this is a unified standard. As long as it complies with IEEE 802.3 specification, you can expand it at will. We all have this experience: pull the network cable and your PC can surf the Internet; Only one optical fiber enters the home, and multiple computers need to surf the Internet? It's all right. Buy a small routing extension and get it done; The office network cable is full, and you need to add server storage, printers and video terminals to access the network? It's all right. Add a switch and expand it. It's done! All these convenience come from the wide application of Ethernet standard. In the all IP era, a car is equipped with a public IP address, and each ECU unit in the car is equipped with an intranet IP address to flexibly configure and connect to the Internet; As long as the interface is reserved, the wired network and wireless network can be switched freely, and any part of the car can exchange data with your mobile device at any time. This is not science fiction. The future is already on the road.
Origin and development of automotive Ethernet
Although Ethernet technology is unimpeded in the communication world, it will face some challenges when applied to automobiles: electromagnetic compatibility and delay are the two main problems. The requirements of twisted pair network for electromagnetic compatibility are not so strict, but it is different on the car; Moreover, the store and forward network must have delay, which is not so picky in the LAN, but it is bound to be much more strict for the automotive network architecture. In 2011, in order to expand its advantages in the field of network communication to the automotive industry, Broadcom developed an Ethernet chip and overall solution for automotive use: first, it successfully solved the EMC problem required by vehicle regulations through broadr reach technology; second, it revolutionized the single pair non shielded twisted pair solution, reducing the weight of traditional harness by 30%.
(next generation broadr reach vehicle Ethernet scheme released by Broadcom)
At the beginning, only the Broadcom family was shouting. However, the wine was good and the alley was not afraid of being deep. NXP, Freescale, Harman, BMW and other auto industry giants also saw this opportunity, so they formed an openalliance alliance to promote the vehicle Ethernet technology standard. At present, many auto factories including FAW and BAIC have joined the alliance. Now, the automotive Ethernet technology has gradually matured. In early 2016, IEEE approved the standard based on broadr reach technology, named 802.3bw 100base-t1. Later, 802.3bp 1000base-t1 also passed. This standard allows a transmission distance of 15m on a pair of signal lines at a speed of 1Gbps; In addition, the on-board Poe standard 802.3bupodl also passed, which means that there is no problem in supplying power through Ethernet port in the vehicle.
(Automotive Ethernet Standardization Organization)
For the Ethernet transmission time delay, packet sequencing and reliability delivery issues most concerned by the industry, technology research and development has not stopped. In terms of audio and video synchronous transmission, another IEEE working group 802.1 has formulated AVB standard; In terms of precise time synchronization, IEEE has proposed a series of standards for TSN (time sensitive network). All the obstacles to the promotion of automotive Ethernet are being steadily solved, and the timetable has been given. Meanwhile, Marvell launched products that meet some 802.1 standards in 2015, such as 88e6321 and 88e6341, which have been used on Tesla autopilot 2.0; In 2017, most standards in TSN automotive application field were finalized, so Broadcom launched bcm53162 in December 2017. The main target markets are unmanned vehicles and L3 driverless vehicles. IEEE originally expected that mass production of TSN for vehicles would not be available until 2021. Now it seems that it should be 1 to 2 years ahead of schedule.
(development of automotive Ethernet standard)
Current situation of vehicle Ethernet in automotive industry
In 2011, when the concept of automotive Ethernet was put forward, many car manufacturers were just on the sidelines. Although everyone recognized that this is a revolutionary technology, conservative car manufacturers and Tier1 were deterred from solving unsolved problems. The first person to eat crabs is always brave. In 2013, BMW X5 was the first to use automotive Ethernet for 3600c look around system. This is also in line with the idea of the open alliance alliance led by Broadcom to promote automotive Ethernet: first, take the infotainment system as the starting point, and gradually go deep into ADAS and even the whole vehicle body and safety system.
(on board Ethernet equipped with BMW X5)
With the advance of time, BMW has tasted the sweetness. In 2015, it deployed on-board Ethernet in all its models (7-series, 5-series, 3-Series and i-series electric vehicles), and it is no longer a simple look around, but the whole vehicle system is designed based on automotive Ethernet. In 2016, more car manufacturers became supporters of automotive Ethernet technology. Jaguar, Land Rover and Volkswagen Passat all integrated automotive Ethernet technology into some of their models, including Tesla Model s and model 3 mentioned above. So far, Broadcom has shipped 19 million Ethernet chips in the automotive market.
When embracing the new world, domestic car manufacturers also have the courage to try new things. Those manufacturers who have no news do not stay on the sidelines. As early as 2015, Chery Automobile and Broadcom signed a memorandum of understanding on cooperation in jointly developing on-board Ethernet Applications; Roewe rx5 is the first vehicle model in China to apply on-board Ethernet to the look around system; Subsequently, Chang'an incall 5.0 also transformed its in vehicle communication architecture with Ethernet technology. Among the new forces, the "operation" of singularity automobile is the largest. In almost all subsystems, on-board Ethernet is adopted, and only some can buses involving safety systems are reserved.
(application prediction of automotive Ethernet)
In 2018, with the release of most IEEE standards on automotive Ethernet, the automotive industry will come to a crossroads: in the wave of automotive intelligence, the disadvantages of traditional bus architecture are becoming prominent; Ethernet is taking its place with its vitality. TSN and time synchronization are the last key. If these standards break through, all the concerns about automotive Ethernet technology will no longer exist.
Automotive Ethernet industry chain
The technical standard itself is jointly promoted by the industrial circle. When the technology is mature, it means that the industrial ecology is mature. Around the automotive Ethernet, many car manufacturers, Tier1 and chip manufacturers have long carefully laid out. Broadcom and NXP needless to say, the C-bit debut represents the most upstream Ethernet chip and the corresponding MCU supplier; As early as last year, MOLEX, the global automotive harness and connector giant, cooperated with BlackBerry's QNX to develop a 10Gbps based vehicle Ethernet platform to improve the data bandwidth of intelligent networked vehicles. Not surprisingly, this black technology product can be seen at today's CES exhibition.
In 2017, Delphi automobile company, a manufacturer of Tier1, reached a strategic agreement with Rosenberger, a high-frequency connection technology company, in order to strengthen its ability in high-speed data transmission“ The interconnected vehicle platform needs to transmit more data at a faster rate through a powerful electronic architecture. This cooperation will enable Delphi to work with another industry leader to establish a universal standard for the Ethernet architecture of the whole vehicle, "said AI Bobin, senior vice president of Delphi, President of electronic / electrical architecture department and President of engineering component team.
There are also many people who join this ecosystem, including not only car factories, but also regular customers on the list of auto suppliers. They are all working hard for the delay and synchronization problems generally concerned by the employment sector. For example, TSN's main supporters include Cisco, Intel, Renesas, German industrial robot giant KUKA, Samsung Harman, BMW, general motors, Hyundai, Bosch, Broadcom, Texas Instruments, NXP, Mitsubishi Electric, LG, Marvell, ADI, general electric, etc. The so-called is not a family, do not enter a family, the embrace of two worlds, from then on, you have me and I have you.
expectation
Sometimes, we need to look back on the way we came before we know whether today's choice is worth it: Ethernet first appeared in automotive applications in 2008, when BMW also regarded it as OBD
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