Mentor Automotive

Vehicle Network Design to meet the needs of ADAS and Autonomous Driving

Presented to AESIN Conference 2016

By Martin Wennberg

October 2016

2 - Confidential

Abstract

With the new automotive trends such as highly automated driving and car-2-x communication the demands on the communication design for a car is changed drastically. New aspects such as redundancy, security and cloud interaction are mixed with the traditional communication design, increasing the need of advanced network design tool support. This presentation will provide an overview of the new communication needs as well as give an introduction to service oriented communication (e.g. SOME/IP) and aspects to consider when mixing it with the traditional signal based communication.

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Technology and Subsystems In-car Experience Connectivity and Networking

EE Architecture Electrical Distribution

Communications Networks Cyber Security

Thermal Analysis LED Lighting

PCB Design

Infotainment Driver information

ADAS & AD Automotive Audio Bus® Multi-Domain

The tux mascot is attributed to Larry Ewing and the GIMP. The Automotive Audio Bus is a registered trademark of Analog Devices, Inc.

AUTOSAR Methodologies Harness Engineering Electronics Cooling System Engineering Noise Cancellation

MENTOR AUTOMOTIVE OVERVIEW

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Important Automotive Trends

Electric Vehicles

Eco-Driving

Autonomous Vehicles

V2X / Connectivity

Architecture Security

BOM cost Image Courtesy Continental Corp.

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MULTIPLE NETWORK TECHNOLOGIES

Complex in-car systems need to communicate with each other: Traditional LIN, CAN, and FlexRay combines with new automotive protocols

like Ethernet and CanFD

Gateway ECU Gateway ECU

Ethernet / FlexRay Backbone

CAN Ethernet

Cameras

CAN LIN

ADAS Driver Info IVI

ECU ECU ECU

Sonar/Radar ECU ECU

ECU

AD

CAN/Ethernet

Secure SOTA

ECU ECU

Redundant

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Why redundancy, security and cloud interaction

A Highly automated driving need backup systems in case something goes wrong

Service based communication is one solution

Connected cars have multiple new entry point

Multiple, layered protection mechanisms should be incorporated to secure the connected car. Data encryption is one.

Cloud interaction move communication outside the car

Ethernet is established outside of the car

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Benefits Of Ethernet

High bandwidth at moderate cost

Protocols out of the box (UDP, TCP or AVB)

Easily connect to external networks

High industry know-how

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Ethernet As Backbone

Connects multiple domains

Signal based communication Data or Service oriented

Stream based communication eAVB streams

Different modes might need to be supported Download/On charger/Driving

Signal gatewaying to/from traditional field buses CAN/Lin/Flexray PDUs and signals

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Ethernet – New communication Paradigm

CAN, FlexRay Ethernet

Communication channel Shared Switched

Configuration Static Static and/or dynamic

Scalability New buses New link

Message size Small to medium Big

Overhead Small Relative big

Bandwidth Limited 1Gbits/s

Analysis OK Complicated

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Signal based Communication: Data vs. Service Oriented Communication

Data Oriented Easy distribution of data Data transformation or signal

mapping can be used Using signals and groups only Compatible with CAN/FR

Service Oriented Communication is per client SOME/IP transformer must be

used Using call/return messages Does not fit with CAN/FR

ECU 1 ECU 2

ECU 3

SWC 1 SWC 2

SWC 3

ECU 1 ECU 2

ECU 3

SWC 1 SWC 2

SWC 3

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How to use signal based Ethernet?

Use Data oriented communication

when connecting traditional field buses

for periodically updated data

for many consumers of the same data

User Service oriented communication

within an Ethernet cluster

for sporadic communication

between few nodes

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Ethernet influence on ECU CPU load

Ethernet allows more data to be sent

Ethernet controllers does not do HW filtering like CAN

Ethernet have higher overhead

Service based communication uses call/return

Ethernet typically does not broadcast data

-> If not designing Ethernet carefully the ECU CPU load is likely to increase

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Ethernet influence on Gateways

Most OEMs will mix service- and signal-oriented communication

Gateways likely need to handle both

Gateways are already today heavily loaded

Ethernet to Ethernet GW is not recommended

-> The Ethernet topology design is important

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Ethernet timing requirements

Timing requirements are important for both signal based and service based communication

Service based communication uses call/return communication

Client call server, server process request and return value

-> Even if Ethernet is quick a service oriented request might take time if not properly designed

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Ethernet Switch configuration

Switch typically part of the ECU Semi static configuration

Learning and static configuration MAC=tier1 and IP=OEM

Several queues (port buffers) per port Queues have priorities (QoS, AVB, VLAN) Traffic shaper: forms queues content Scheduler: decides from which queue to send next frame

Weighted Round Robin (WRR) Strict Priority (SP)

-> Configuring an Ethernet switch is complicated

Source: 17_Rick_Kreifeldt_-_Harman_International_AVnu.pdf

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Signals/Streams

Link Utilization

Busload, CPU

Latencies, buffers

Compatibility

Downstream

Signals/Streams

Link Utilization

Busload, CPU

Latencies, buffers

Compatibility

Downstream

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Capturing Communication Design

Working with Documents

Working with VSA COM

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Summary

Traditional and service based communication will co-exist

Increased data communication is increasing CPU load on ECUs

Automotive Ethernet is complex to design

Understanding Ethernet is not the same as understanding automotive (AUTOSAR) Ethernet

Advanced network design tool support is even more important for the coming generation of cars

men to r. c om/au tomo t i ve

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Physical Networks

BUS CAN CAN FD LIN FLEXRAY ETHERNET

Speed Up to 1 Mbps Up to 8 Mbps Up to 19.2 Kbps 10 Mbps Up to 1 Gbps

Cable Type Twisted Pair 5V Twisted Pair 5V Single Wire 12V 2 or 4 Wires One or more Twisted Pair

Cost $$ $$ $ $$$$ $$$

Applications ABS, Powertrain, Engine Control

Higher data capacity CAN applications

Electric Seats, Mirror, Tailgate

Steering, Traction Control, Active Suspension

IP Cameras, Radar, Infotainment