Towards Ethernet-based software-defined vehicles

The autonomous vehicle of the future will be one of the most complex “mobile” devices in the world. Its complexity stems from the need to autonomously operate every day processing terabytes of data—partly from a large number of sensors and devices inside, outside, and around the vehicle, and from the cloud—while running 100 million lines of software code while consuming teraflops (TFLOPs) of computing power. This is changing the way engineers think about vehicles, especially how vehicle systems communicate with each other.

Self-driving cars – a new design paradigm

Over the years, the trend toward automotive automation has resulted in a complex array of standalone computers for vehicle subsystems. These systems require multiple dedicated electronic control units (ECUs), different types of buses and protocols, and gateways to translate data and signals between buses so that the systems can communicate with each other. This heterogeneous approach is costly, difficult to protect against cyber threats, and frankly, heavy. Cabling is the third most expensive part of a car’s bill of materials and the third heaviest component in its manufacture, reaching up to 110 pounds of copper in some cars.

A fully autonomous vehicle is a more complex system that requires large amounts of real-time data, cloud connectivity, and fast, safe, and reliable decision making. The amount of data moving around the car will be orders of magnitude greater than today's cars and will require enormous bandwidth. Autonomous driving will require more video, radar, and LiDAR data processing, and these functions will require multi-gigabit physical network throughput to support real-time decision making. Data logging, secure transactions, and communication with the cloud will increase I/O requirements.

Providing computing power and managing complexity requires a rethinking of the car. Several distributed regional ECUs around the vehicle will run millions of lines of code to process data from local endpoints and the cloud, and interconnect with one or more master ECUs instead of dedicated ECUs. Bandwidth, complexity, and cost are issues that arise when trying to connect all of these devices using many of today's existing network protocols and cables.

Software Defined Car

The car is evolving into a system of software-defined functions running on distributed computing - the software-defined vehicle (SDV). The trusted computing standard is an IP-based network built on Ethernet. Ethernet provides a single bus for communication and eliminates the complexity of vehicle gateways and cables, and has been proven to support the flexibility and performance of software-oriented architectures, including software-defined networking and virtualization.

SDV brings many benefits. Software updates, changes and improvements are easier and faster than hardware-oriented systems. Using virtualization, SDV becomes a more dynamic computing environment. For example, when an ECU begins to fail, software-defined functions can be quickly transferred to other ECUs in the vehicle, maintaining the required level of functional safety and critical operations.

SDV creates new opportunities for manufacturers to differentiate their products, increase safety, and improve product, service, and overall manufacturing efficiency. SDV requires manufacturers to become software giants. Manufacturers are already “retooling” their R&D expertise infrastructure to include software development teams that never existed before.

Safety in SDVs

Digital security is critical for autonomous vehicles, a continuum from manufacturer to owner. The many devices on board and connections to passengers and the cloud greatly expand the attack surface for bad actors. Common security features adopted in SDVs will be based on open source solutions that support secure boot, authentication, encryption (if required), keys and key management, and secure enclaves. In addition, network-specific security services may include the following capabilities:

Virtual LAN to isolate regional ECUs from the physical network

Access control to allow only authorized transactions on the local network

Deep packet inspection to monitor transactions and detect and block unwanted data

Intrusion detection and prevention to stop bad actors from gaining access

In the field, updates will need to be protected from hackers, most likely through a secure chain of trust established on the production floor and ending with the vehicle owner.

Tools to help ensure functional safety

To enable communications in SDVs, the market requires automotive-specific physical devices (PHYs) for Ethernet and other protocols. These devices need to provide the required bandwidth and cost, and meet the functional safety requirements established within the industry and set by regulatory agencies. Microchip is a major contributor to automotive solutions. The company's catalog offers many "functional safety ready" devices for cars, including Ethernet devices that meet automotive standards.

The devices have been carefully selected to help manufacturers achieve ISO 26262 certification and are available with a number of tools including failure modes effects and diagnostic analysis (FMEDA) reports, functional safety manuals, diagnostic software and development tools.

The All-Ethernet Vision for Autonomous Driving

The automotive industry’s vision is evolving toward an all-Ethernet SDV, with interconnected regional ECUs, sensors, and devices controlled by a central ECU. For greenfield manufacturers, this migration is easier than for established companies. Greenfield environments can be fully adopted immediately to easily adopt an all-Ethernet approach. For other automakers, the migration to an all-Ethernet vehicle may take some time, requiring the SDV to include a hybrid network architecture of CAN, LIN, and other buses to connect to certain components locally over the main Ethernet backbone.

Ethernet’s reliable, proven standards, high bandwidth from Mbps to Gbps, and simplicity support the necessary performance, security services, and easy connectivity required for SDVs. Ethernet’s serial cabling options reduce the cost and complexity, cabling, and weight of multiple automotive networks. Reduced weight improves fuel efficiency—whether electric or gasoline/diesel. And, while Ethernet is a mature, standardized technology, it continues to evolve to support markets such as automotive, where specific requirements include determinism and high bandwidth—necessities for autonomous vehicles.