Already extremely sophisticated, today’s automobile is being transformed by the steadily growing demand for advanced features to support autonomous applications and capabilities. Increased use of cameras plus advanced sensor networks for assisted driving are placing rising requirements on the internal networks, resulting in three main needs: increased bandwidth, cross-domain communications, and security.
The solution for automotive engineers in meeting these new challenges is a well-established technology that has evolved to meet the needs for the next-generation automotive network: standard Ethernet. New additions to Ethernet core capabilities, introduced originally under the general name of Audio Video Bridging (AVB), and now known under the expanded term: Time-Sensitive Networking (TSN), include prioritization, reservation, traffic shaping, and common precision time. These new capabilities allow the automotive industry to construct networks that meet the demanding predictability and reliability requirements of the automotive industry, while modernizing the vehicle with flexible, scalable and secure networking technology and keeping cabling cost and weight at a minimum.
The TSN standard is supported by the automotive industry including silicon providers, tier one suppliers and OEMs such as BMW, GM, Harman, Intel, Bosche and more all working togethertogether under the umbrella of an organization, the Avnu Alliance, to create an interoperable ecosystem of hardware, software, and services to enable next generation automotive systems. Through this worldwide collaboration that spans beyond the automotive space and also into industrial and professional AV spaces, the industry is able to take advantage of a healthy ecosystem and Ethernet’s economies of scale. Other organizations including GENIVI, Open Alliance and Japan Automotive Software Platform Architecture (JasPar) Consortium collaborate with the goal of creating this common foundation allowing multiple protocols and manufacturers to coexist on the same TSN network.
IEEE Provides Base for Automotive Standards
IEEE standardizes Ethernet-based technology and thus provides a professional basis for data communications solutions in the car. But these specifications by themselves do not serve as target specifications for automotive applications. In contrast, the IEEE documents define the interbranch standard for communications mechanisms, and are crucial in defining a complete application profile, supplemented by additional domain-specific requirements. These profiles are prepared by working group members within Avnu Alliance, and any lessons learned through the industry are communicated back to IEEE who can then adapt and enhance the standard as necessary.
As the basis for other application areas such as industry 4.0, consumer electronics, or professional audio, this process ensures the maintenance of the integrity of the TSN standard. The protection of TSN allows products based on them have a broader application range, are more competitive and can thus be exposed to the market with lower cost.
There is also a process in place for product verification, which offers a synergy effect since basic test processes are consistent. The design effort for the definition and certification of automotive-specific scopes decreases only slightly compared to introducing a proprietary solution.
The Automotive Profile for TSN
A profile focusing on IVI and camera applications has been realized such as top or surround view, consisting of the following elements:
1. Requirement Summary
The “Automotive Ethernet AVB Functional and Interoperability Specification” summarizes all requirements for the corresponding application. For Automotive, the following key requirements are defined, among others:
- Quick Network and Device Startup
- gPTP Pre-configuration
- Pre-configured Stream Reservation
- Audio and Video Formats
- Latency Requirements (Audio/Video)
- Exception Handling
- Diagnostic Counters
To meet the automotive application requirements, the profile documents decisions and assumptions describing how the standards are applied. It doesn’t specify the applications themselves, but rather the base parameters for network performance, reliability and interoperability, which allows vendors to build upon a common foundation, to innovate and build differentiated products where the value of differentiation is high, while reducing R&D spent on non-value add features (like networking).
2. Test Plans
Detailed descriptions of test cases ensure proper operation of the network. They are based on the Interoperability Specification, which is created specifically for each market (Automotive, Industrial, Pro AV, etc.). The Automotive AVB test plans contain over 280 test cases, ensuring the devices perform as expected. The Interoperability Specification and detailed test plans also provide common requirements for Si and module suppliers and a baseline for development of higher-level functions. Validation efforts and cost to develop and execute are reduced with common test parameters and plans.
3. Ecosystem of Testing Services and Tools
Registered test facilities such as Ruetz Systems Solutions and University of New Hampshire Interoperability Lab as well as test tool vendors such as Spirent and Ixia, provide tools and services that can be used for certification where desired, as well as testing and validation tools for members to use earlier in the product life cycle.
Advanced Drive Assistance Systems (ADAS) Roadmap
As we move towards autonomous driving, there is an increased need for highly reliable, deterministic, cross-domain communication in the vehicle, examples include precisely timed sensors fused together to develop sophisticated applications. Engine control can use location information and road profiles to improve fuel savings and by headlights to illuminate around corners, increasing safety. Surround view and other camera applications are pushing data bandwidth needs higher and higher; point-to-point solutions, such as LVDS, are becoming increasingly costly to implement and lack the flexibility needed for these new applications.
Key players in the automotive industry in cooperation through these supportive organizations are in the process of examining these applications in detail in order to define appropriate scenarios, derive requirements, and finally define a corresponding profile to support these new applications. A few examples of application areas for TSN Ethernet include:
- Control network with low latency, deterministic and guaranteed bandwidth
- Sensor data redundancy
- Backbone for connection and data transport of different network domains
- Performance definition for time-based failure (Grand Master)
- Prevention against: Oversubscribed Traffic / Babbling Idiot Protection / Ingress Policing
- Security
Future-ready network infrastructure
The automotive industry will benefit from the adoption of a new automotive network standard, enabling the interoperability of electronic systems and components and quickly bringing more lower cost and easy-to-use technology and devices to market. Consumers are pushing in this direction, too. In fact, according to a recent study published by PWC, “56 percent of new car buyers said they would switch to a different brand if the one they were considering didn’t offer the technology and features they wanted. Similarly, 48 percent of car buyers said they would walk away from a vehicle they liked if the technology was difficult to use.”
The new automotive Ethernet will allow a broad adoption of new sensors and ADAS applications, such as the Collision Avoidance System. As a potential result, the National Highway Traffic Safety Administration projected that the ensuing acceleration of the rollout of automatic emergency braking would prevent an estimated 28,000 collisions and 12,000 injuries.
A common technical platform is facilitated by Avnu and automotive members through a number of services, including open source software, hardware reference designs, test plans, and certification services to develop and verify the correct operation and implementation of time-sensitive networked products and ultimately accelerates bringing more products to market.
