VANET:On mobility Scenarios and Urban Infrastructure. Realistic Simulation of Network Protocols in...
-
Upload
kevin-cameron -
Category
Documents
-
view
219 -
download
0
description
Transcript of VANET:On mobility Scenarios and Urban Infrastructure. Realistic Simulation of Network Protocols in...
VANET:On mobility Scenarios and Urban Infrastructure.
&Realistic Simulation of Network Protocols in VANET Scenarios
Advisor: Kai-Wei KeSpeaker: Chia-Ho Chao
Date: 22/04/2008
2008/4/22 1
VANET:On mobility Scenarios and Urban Infrastructure.
2008/4/22 2
Outline
Overview of TRANSIMS Overview of CORSIMRandom waypoint (RWP)Mobility Models Comparison
Flat NetworkOpportunistic InfrastructureInter-contact TimesAfternoon Trend
Conclusion2008/4/22 3
TRANSIMS Traces
TRANSIMS : Transportation Analysis Simulation System
Asses the performance of a large scale urban sensor network.Creating car movement patterns based on activity flows by large scale, vehicular traffic and parallel simulator.
2008/4/22 4
CORSIM Traces
CORSIM : Microscopic Traffic Simulation Model
high level of precision in vehicular traffic simulation.difference from TRANSIMS:
Single CPULack of activity flow information
2008/4/22 5
RWP
2008/4/22 6
Mobility Models Comparison:Simulation setting
2008/4/22 7
Simulation setting
VANET simulations are run for 200 seconds on a 1*2 km rectangle on the map.Highest AP density 7AM 8AM
Average vehicles 270 371
Average speed per second
12.6m/s
12.5m/s
Stop time(seconds) 3.2 5.7
Mobility Models Comparison:FLAT NETWORK
2008/4/22 9
Using TRANSIMS mobility traces
2008/4/22 10
8am no APs
7am noAPs
Using RWP model
2008/4/22 11
8am no APs
7am noAPs
Using CORSIM mobility traces
2008/4/22 12
8am no APs
7am noAPs
Mobility Models Comparison:OPPORTUNISTIC
INFRASTRUCTURE
2008/4/22 13
Simulation Setting
2008/4/22 14
Simulation Setting
2008/4/22 15
Using TRANSIMS mobility traces
2008/4/22 16
8am with APs
7am withAPs
Using RWP model
2008/4/22 17
8am with APs
7am withAPs
Using CORSIM mobility traces
2008/4/22 18
8am with APs
7am withAPs
Mobility Models Comparison:Inter-contact Times
andAfternoon trend
2008/4/22 19
TRANSIMS mobility traces at 7AM
2008/4/22 20
TRANSIMS mobility traces at 8AM
2008/4/22 21
Afternoon trend
2008/4/22 22
Afternoon trend
2008/4/22 23
Conclusion
The results confirm that open APs can be effectively exploited to dramatically improve performance.A correct model of traffic flows is important.In long timeframes during the day (i.e. rush hours), network becomes static.
2008/4/22 24
Realistic Simulation of Network Protocols in VANET Scenarios
2008/4/22 25
Outline
Traffic SimulationNetwork SimulationCoupling Traffic Microsimulation and Network SimulationSimulation ResultConclusion
2008/4/22 26
Traffic Simulation
Macroscopic modelsMETACOR
Mesoscopic modelsCONTRAM
Microscopic modelsCellular Automaton model (CA)SK modelIDM/MOBIL model
2008/4/22 27
Intelligent-Driver Model(IDM)
Car-following model
2008/4/22 28The gap to a
vehicle in front
Difference in speed
Desired velocity
Time headway
a:comfortable accelerationb:comfortable deceleration
Acceleration exponent
Additional gap(driving)
Minimum gap(jam)
Desired gap
acceleration
MOBIL
MOBIL: Minimizing Overall Braking decelerations
Induced by Lane changeHave to be fulfilled two criteria:a) The lane change has to be safe.
2008/4/22 29
Maximum safe
deceleration
Desired gap
Desired gap
Accelerationb)
Bias to the right
lane
politeness factor
Lane change
threshold
Road Traffic Microsimulation ParametersCar Track
Desired velocity V0 33.0m/s 22.2 m/s
Time headway T 1.5s 1.7s
Comfortable acceleration a 0.73m/s^2 0.73 m/s^2
Comfortable deceleration b 1.67m/s^2 1.67 m/s^2
Acceleration exponent 4 4
Minimum gap (jam) S0 2m 2m
Additional gap (driving) S1 0m 0m
Vehicle length l 6m 10m
Politeness factor P 20% 20%
Maximum safe deceleration bsave 4m/s^2 4 m/s^2
Lane change threshold athr 0.3 m/s^2 0.2 m/s^2
Bias to the right lane △ b 0.1 rm/s^2 0.3 m/s^2
2008/4/22 30
δ
OMNeT++
A discrete event simulation environment.primary application area is the simulation of communication networksGUI supportINET Framework
2008/4/22 31
DYMO Routing Protocol
DYMO: Dynamic MANET On-Demand Reactive
2008/4/22 32
A B C DAODV
A A A
D D D
DYMO
AB ABC
DCDCB
DYMO and support modules in the protocol stack
2008/4/22 33
App1 App2 DYMO
Transport Layer
Network Layer
Data Link Layer
queue
hook
TCP.mss 1024Byte
TCP.advertisedWindow 14336Byte
TCP.tcpAlgorithmClass TCPReno
ARP.retryTimeout 1s
ARP.retryCount 3
ARP.cacheTimeout 100smac.address auto
mac.bitrate 11Mbit/s
mac.broadcastBackoff 31slots
mac.QueueSize 14Pckts
mac.rtsCts False
Simulated VANET Scenario
2008/4/22 34
Coupling Traffic Microsimulation and Network Simulation
2008/4/22 35
Car ; i=car0_[…] Car ; i=car1_[…] Car ; I=car1_[…]
3187,14873187,14903187,14933187,14953187,14983187,15013188,1504
[…]
3171,13803172,13873173,13943174,14023175,14093176,14173177,1425
[…]
3154,12623156,12693153,12773155,12843156,12913158,12993159,1306
[…]
Excerpt from the traffic simulation’s output stream
Simulation Result
2008/4/22 36
15%
Simulation Result
2008/4/22 37
Simulation Result
2008/4/22 38
Conclusion
Integrated the traffic model in network simulation in order to improve the quality of network simulations. Simulation setups using simple mobility models often produce skewed results compared to the application of traffic models.
2008/4/22 39
ReferenceG. Marfia, G. Pau, E. De Sena, E. Giordano, M. Gerla, “Evaluating Vehicle Network Strategies for Downtown Portland: opportunistic infrastructure and the importance of realistic mobility models,”http://transims.tsasa.lanl.gov/.http://mctrans.ce.ufl.edu/featured/TSIS/Version5/corsim.htm.http://www.omnetpp.org/I. Dietrich, C. Sommer, and F. Dressler, "Simulating DYMO in OMNeT++," University of Erlangen, Dept. of Computer Science 7, Technical Report 01/07, April 2007.
2008/4/22 40
2008/4/22 41
Thanks for your attention!