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Simulation based Timing Analysis ofFlexRay Communication at System Level
Stefan Buschmann Till SteinbachFranz Korf Thomas C. Schmidt
Hamburg University of Applied [email protected]
{till.steinbach, korf, schmidt}@informatik.haw-hamburg.de
6th International Workshop on OMNeT++March 5th, 2013
RE NET
Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REAgenda
1 Introduction
2 Background & Requirements
3 Concept
4 Results & Evaluation
5 Conclusion & Outlook
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REMotivation
Why simulate FlexRay on system level?State-of-the-art automotive fieldbusSimulation of complex networksImportant in automotive development
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REGoals
Configurable FlexRay simulationCompliant to FlexRay specificationCompatible with other simulation models
CAN, Real-time Ethernet, Ethernet-AVB
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REAgenda
1 Introduction
2 Background & Requirements
3 Concept
4 Results & Evaluation
5 Conclusion & Outlook
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REFlexRayTechnical features
Layer 1 and 2 in the OSI modelCommunication over two channels
Redundant transmissionDifferent data per channel
10 MBit/s per channelSynchronised time baseEvent- and time-triggered communication
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REFlexRayCommunication cycle
Node 1Node 2Node 3Node 4
Slot 1 2 3 4 5 61 2 3 4 5 6Slot 1 2 3 4 5 6 8 9 101 2 3 4 5 6 7 8
static segment
static segment
dynamic segment
dynamic segment
symbol window
network idle timeSegment
cycle 0 cycle 1
Time-triggered communicationEvent-triggered communication
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REFlexRaySynchronisation
Time measurement with synchronisation messages inthe static segmentCombination of two synchronisation methods
Offset correctionnode 1
node 2devi
atio
n
t
Rate correctionnode 1
node 2devi
atio
n
t
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
RERequirementsFor the FlexRay model
Layer 2 in the OSI modelFlexRay functions
CommunicationSynchronisation
Implementation of a model of an oscillatorConfiguration of the network structure and theparametersSystem level error detection
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REAgenda
1 Introduction
2 Background & Requirements
3 Concept
4 Results & Evaluation
5 Conclusion & Outlook
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REConceptArchitecture
FlexRay nodes as modulesBus topology as module
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REConceptNode
Several submodulesConnection to the bus moduleIndependent configuration
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REConceptTopology
OMNeT++ only provides point to pointcommunicationBus topologyRealised as moduleProvides a maximum of two connections for eachnodeDistribution of incoming messages
busbus
unit1unit1
unit5unit5unit3unit3
unit2unit2
unit4unit4
channel A
channel B
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REConceptModel of the oscillator
Very accurate model would simulate every tickHuge amount of events
Our approach for the clock driftOnly one drift value per cycleReducing the number of events
t
Cycle Cycle
Constant Ticklength variable DriftfactorEvent Event
Cycle
Event
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REAgenda
1 Introduction
2 Background & Requirements
3 Concept
4 Results & Evaluation
5 Conclusion & Outlook
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REProtocol conformance & errordetection
Protocol conformance:Requirements are fulfilled
Typical error detection:Configuration problems
Too many sync nodesFrames in the same slot
Timing errorsFrames in wrong slot
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
RELatency Analysis for the dyn. segmentSimulation parameter
4 nodes10 minislotsTransmission points distributed over dynamicsegmentDynamic frames require 1 to 3 minislots
1 2 3 411 12 13 14 15 16 17 18 19 20
dynamic segment
minislot ID
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
RELatency Analysis for the dyn. segmentLatency of frames with different IDs
0 , 0 0 , 3 1 2 3 4 50
1 02 03 04 05 06 0
02468
1 0
3 , 2
3 , 3
3 , 2
3 , 3
Time f
or Bu
s Acce
ss [m
s]
S i m u l a t i o n T i m e [ s ]
I D 1 9
I D 1 7
I D 1 5
I D 1 1
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
RELatency Analysis for the dyn. segmentLatency distribution
0 1 0 2 0 3 0 4 0 5 0 6 0 7 00123456789
9 51 0 0
Re
lative
Numb
er of
Packe
ts [%
]
T i m e f o r B u s A c c e s s [ m s ]
I D 1 1 I D 1 5 I D 1 7 I D 1 9
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REPerformance test
Several networks of various sizeOnly messages in the static segmentFurther parameters identical
number of nodes channels t_sim/t_real [s]10 single ∼0.9620 single ∼0.5830 single ∼0.4510 dual ∼0.6220 dual ∼0.32
Nearly worst case scenarioTiming parameter and configuration have a largeinfluence
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REEvaluation against CANoeComparison of latency results
CANoeCommercial network simulatorVariety of automobile communication protocols
Two equal networksThree nodesSame parameters
Same behaviour in both networksAmount and timing of messagesRepressed dynamic frames
Difference of approximatly 100 ns
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REAgenda
1 Introduction
2 Background & Requirements
3 Concept
4 Results & Evaluation
5 Conclusion & Outlook
18 / 21
Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REConclusion
System level simulationSupport of different applicationsEvaluation against CANoeCan be used for simulation of completecommunication-matrices
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REOutlook
Extension of the simulationActive star topologyStartup procedure and node integration duringoperation
Gateway between FlexRay and other communicationmodelsSimulation of complex real communication-matrices
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Hochschule für Angewandte Wissenschaften Hamburg Hamburg University of Applied Sciences
FlexRay-Simulation inOMNeT++
S. Buschmann
Introduction
Background &Requirements
Concept
Results & Evaluation
Conclusion & Outlook
REThank you!
Thank you for your attention!
Website of CoRE research group:http://www.haw-hamburg.de/core
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