Automotive Ethernet is evolving towards high bandwidth and multiple ports

Depending on the form of communication connection, automotive communication applications are divided into wireless communication and wired communication.

Automotive communication application diagram

Source: Automotive Knowledge Stack

The automotive electronic and electrical system uses the communication network as a carrier to connect the in-vehicle electronic devices through wiring harnesses. With the evolution of the automotive E/E architecture and the increase in the complexity of in-vehicle functions, the number of sensors in the car continues to increase, resulting in a surge in the amount of in-vehicle data, which has high requirements for the real-time communication and data processing capabilities of the entire vehicle. Therefore, high-bandwidth, low-latency, and high-reliability in-vehicle Ethernet will be more suitable for the long-term evolution of the future E/E architecture and the needs of high-speed in-vehicle communication.

In the Zonal architecture, after the functional centralization is achieved, the number of ECUs in the car is greatly reduced. At this time, the central computing platform has extremely high requirements for the computing power of the controller, while the computing power requirements for the regional controller are relatively low. In order to meet the requirements of in-vehicle functional safety, a large amount of data transmission and migration between the central and regional controllers, and the interaction of software algorithms, in-vehicle Ethernet will become the data backbone link in the Zonal architecture.

With the evolution of the automotive E/E architecture, in-vehicle Ethernet (red line in the figure) will become the backbone network



Note: 1TPCE refers to "100M Ethernet of 1 twisted pair"; RTPGE refers to "simplified twisted pair Gigabit Ethernet". Source: Keysight

When Ethernet is used as the in-vehicle backbone network of future cars, the information exchange between the regional controllers is realized through Ethernet switches. At present, Marvell, Broadcom, NXP and other in-vehicle network communication chip manufacturers have proposed the next-generation network architecture. Aquantia's in-vehicle network architecture for future ADAS systems



Source: Marvell Take Aquantia (acquired by Marvell)

as an example of the in-vehicle network architecture of future ADAS systems, which has two central computing units (GPU/CPU) and three switches to connect all cameras and sensors. The entire car is connected by Ethernet. Each sensor needs to deploy a PHY chip, and each switch node also needs to be configured with several PHY chips to input data transmitted from the sensor end.

In-vehicle Ethernet involves redundant backup design, which requires hardware functions to achieve master-slave or parallel processing. Data from cameras and sensors is sent to a central computing unit, while another central computing unit is used as a backup to take over control of the car when the first unit fails.

In-vehicle Ethernet is evolving towards high bandwidth and multi-port In-vehicle Ethernet chips mainly include physical layer interface PHY chips and Ethernet switch chips. PHY chips mainly convert digital/analog signals based on the physical layer without processing data; switch chips process transmission data based on the data link layer, including fast forwarding and switching, filtering and classification of data packets.

With the evolution of automotive E/E architecture, the penetration rate of automotive Ethernet chips continues to increase, and China's automotive Ethernet chip market is growing rapidly. Taking the PHY chip market as an example, the current automotive Ethernet PHY chips are mainly used in central computing systems, ADAS systems and IVI systems. According to the average usage of PHY chips per vehicle in each system and the average price of PHY chips, the market size of automotive Ethernet PHY chips in China's passenger car market in 2022 will be 5.8 billion yuan. In the

future, as in-vehicle Ethernet further penetrates into other areas of the car, the usage of single-vehicle chips will continue to increase, and the proportion of high-speed PHY chips will gradually increase, which will offset the decline in the price of single-model chips. It is estimated that by 2025, the market size of automotive Ethernet PHY chips in China's passenger car market will reach 21.87 billion yuan.

Automotive Ethernet evolves towards high bandwidth and multiple ports

The evolution direction and speed of automotive E/E architecture affect the development direction and speed of automotive Ethernet in the future. In order to keep up with the rapid development of autonomous driving technology and meet the data transmission requirements of multi-functional interaction in smart cockpits, automotive Ethernet will develop towards high bandwidth and multi-port configuration in the future.

Autonomous driving promotes the development of 10G+ automotive Ethernet. The autonomous driving technology of smart cars is becoming more and more mature, and the requirements for the real-time and sensitivity of massive data transmission are getting higher and higher. In addition, there will be a demand for massive data storage when autonomous driving is on the road. In order to realize the real-time storage of high-definition data from sensors such as cameras and lidar, the requirements for in-vehicle network bandwidth will be higher.

The higher the level of autonomous driving, the greater the demand for high-speed networks for in-vehicle communication. For autonomous driving above L3, the in-vehicle network will begin to introduce a large number of 2.5/5/10G automotive Ethernet. And in the end, for L4/L5 autonomous driving cars, the number of in-vehicle Ethernet will increase, and many will introduce 10G+ standards. Therefore, high-speed automotive Ethernet is an indispensable requirement for achieving autonomous driving above L3.

Most mainstream or emerging car companies have already laid out the "centralized" E/E architecture in advance, and the mass production of models will be concentrated in 2023-2025. In order to realize the Zonal architecture in 2025, 10G bandwidth is necessary. In the 10G automotive Ethernet chip market, there are only two Ethernet switch manufacturers that can provide 10G+, Marvell and Broadcom.

Marvell Central Automotive Ethernet Switch Q6223 Block Diagram



Source: Marvell In June 2023, Marvell launched the Brightlane Q622x series of central automotive Ethernet switches, which are specially designed for automotive Zonal architecture. The regional switch aggregates the traffic from devices (such as processors, sensors, actuators, and storage systems) in the physical area of ​​the car, and connects to the central computing switch through high-speed Ethernet to achieve information interaction.

The Brightlane Q622x series switches are single-chip devices, specifically including two products, Q6222 and Q6223:

Brightlane Q6223 has a bandwidth of 90 Gbps, which is almost twice the capacity of currently available automotive switches. It adopts a non-blocking 12-port design and can be configured from 8 integrated 10GSerDes ports, 4 integrated 2.5G SerDes ports, and 2 available integrated 1000Base-T1 PHYs;

Brightlane Q6222 includes 9 60 Gbps ports, and 5 integrated 10G SerDes ports, 4 integrated 2.5G SerDes ports, and 2 integrated 1000Base-T1 PHYs are available.

The number of in-vehicle Ethernet ports increases with the evolution of automotive E/E architecture As the automotive E/E architecture evolves, the penetration rate of in-vehicle Ethernet gradually increases, and the demand for Ethernet node chips will increase in the future. The number of Ethernet ports per smart car will exceed 100.

But so far, the number of Ethernet ports in mass-produced cars is not too large. They are basically used in subsystems such as IVI systems, vehicle communication systems, gateways and domain controllers, and a vehicle-level network architecture with Ethernet as the backbone has not yet been formed. In the future, with the mass production of Zonal architecture models, the use of in-vehicle Ethernet in the vehicle network communication architecture will increase significantly. At this time, the number of communication ports of in-vehicle Ethernet in the car will also increase accordingly.

In terms of chip manufacturers, the number of communication ports in new products or updated iterative products issued by international manufacturers including Broadcom and NXP is also showing an increasing trend.

Comparison of product port numbers of some in-vehicle Ethernet-related chip suppliers



Source: Zoss Automotive Research "2023 Automotive In-Vehicle Communication and Network Interface Chip Industry Research Report"

In May 2022, Broadcom launched a high-bandwidth single-chip automotive Ethernet switch device, the BCM8958X, which has a total of 16 Ethernet ports, 6 of which have 10Gbps capabilities (XFI or PCIe x1 4.0 interfaces with SRIOV), as well as integrated 1000BASE-T1 and 100BASE-T1 PHYs. Interface configuration of Broadcom BCM8958X