A Simulation Framework for V2V Wireless SystemsCHRISTIAN NELSON, CARL GUSTAFSON, FREDRIK TUFVESSON
DEPARTMENT OF ELECTRICAL AND INFORMATION TECHNOLOGY, LUND UNIVERSITY, SWEDEN
IN COLLABORATION WITH ALEXEY VINEL AND NIKITA LYAMIN
SCHOOL OF INFORMATION SCIENCE, COMPUTER AND ELECTRICAL ENGINEERING,
HALMSTAD UNIVERSITY, SWEDEN
Motivation
• We need realistic simulations that we can rely on for network evaluations.
• Outputs are for example, with realistic time behavior
– Received power
– Packet loss / Bit error rate
• With this information researchers and engineers working with different control
loops for the vehicles have more sound input into their models and simulations.
• This is ongoing work, hence there will be no pretty plots at the end.
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 2
Vehicular wireless communications
• Enables increased road safety and traffic efficiency by using
– Vehicle-to-Vehicle (V2V) communication,
– Vehicle-to-Infrastructure (V2I) communication.
• Improved safety: Collision warning, intersection assistance, congestion alert, etc.
• Cooperative ITS: Reduced emissions, improved traffic flow.
• Autonomous vehicles
• Improved positioning
• We need a cross layer approach. Within ELLIIT we have worked in
collaboration with Halmstad University to achieve this.
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 3
Vehicular wireless communication systems
• Intelligent Transportation Systems (ITS) typically use the dedicated 5.9 GHz
band.
• Key technologies are
– IEEE802.11p standard,
– First version of LTE-V2X, available early 20171.
• In early ITS, these technologies will have to coexist.
1 ericsson.com, “LTE for Intelligent Transport Systems”, June 9, 2016.
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V2X wireless channels
• V2V channels are significantly different from conventional cellular channels
– Different propagation environments,
– Tx and Rx approximately at the same height,
– Higher mobility.
• V2I channels are more similar to cellular channels (base station static), but still
differ in mobility and environment.
→ Specific channel models are needed!
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 5
Different scenarios
• Urban
– Parked vehicles.
– Buildings.
– Intersections.
• Rural
– Often LOS.
– Few vehicles.
• Highway
– Many moving vehicles.
– Higher speeds.
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 6
Why do we need a simulation framework?
• Measurement campaigns are crucial since
– Realistic channel models are derived from these measurements.
– They can be used as input to the simulation framework.
• But, V2X measurement campaigns are,
– Time consuming and expensive,
– Involve fewer vehicles compared to a full-scale deployment,
– Not easy to capture all aspects of V2X systems and scenarios.
• By using a simulation framework, these drawbacks can be addressed!
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 7
V2V Simulation Framework Challenges
A V2X system simulation should ideally include all important layers for various scenarios:
Physical (PHY)Medium Access Control
(MAC)Network (NET)
Highway
Urban
Rural
Intersections
Multi-link
Platooning
Congestion
etc.
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 8
Simulation Framework Summary
OMNeT++ / OMNEST
Plexe-Veins
Plexe-SUMO
RoadTrafficSimulation
Interface
PHY Layer
MAC Layer
Mobility
Inspired by http://veins.car2x.org/documentation/veins-arch.png
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 9
V2V System Simulation Framework
OMNeT++ - Discrete Event Simulator, (https://omnetpp.org)
Veins - Vehicles in Network Simulation, (http://veins.car2x.org)
Sumo - Simulation of Urban Mobility, (http://www.sumo.dlr.de)
Plexe - Platooning Extension for Veins, (http://plexe.car2x.org)
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 10
OMNeT++
Objective Modular Network Testbed in C++
• A C++ class library
• Simulation control
• Utility classes
– random number generation
– statistics collection
– topology discovery
– etc…
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 11
SUMO – Simulation of Urban Mobility
• Traffic simulation tool. It supports simulation of
– Vehicles, public transportation and
pedestrians.
– Traffic lights.
– User generated traffic flow or model based.
– Road network and buildings can be imported
from OpenStreetMap.
– (1:42)
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 12
Veins – Vehicles in Networks Simulation
• Module under OMNeT++.
• Connects SUMO with models for the PHY and MAC layers.
• Includes an implementation of e.g. IEEE802.11p.
• LTE-extension available.
• Simpler models for the propagation channel.
• We are working on improved channel models.
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 13
Plexe – The Platooning Extension for Veins
• Adds the ability for realistic platooning simulations.
– Vehicle dynamics.
– Different cruise control systems.
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 14
Simulation Framework Summary
OMNeT++ / OMNEST
Plexe-Veins
Plexe-SUMO
RoadTrafficSimulation
Interface
PHY Layer
MAC Layer
Mobility
Inspired by http://veins.car2x.org/documentation/veins-arch.png
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 15
What is missing?
• Improved pathloss models.
• Autocorrelation.
• Separation/model selection for LOS/OLOS.
• Cross-correlation modelling of multilink systems.
• The vehicles in a platoon in Plexe-SUMO, drive in a perfect straight line.
– Need to add some randomness/noise in the lateral movement.
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 16
Two-ray and single-slope pathloss models
Two-ray LOS Single-slope OLOS
[Nilsson et al, Trans Veh Tech, submitted]
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Two-ray pathloss model
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 18
[Nilsson et al, Trans Veh Tech, submitted]
Autocorrelation
• We also include an autocorrelation function.
• This is based on extensive measurements for several different link pairs.
• Will be modelled as an exponential decay 𝜌 = 𝑒− Τ∆𝑡 𝑇𝑐
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 19
Cross-correlation
• Multilink
– Based on extensive measurements.
• Cross-correlation
• If we take care of the geometrical
information regarding LOS and OLOS,
then we can neglect cross-correlation on
highway for typical scenarios.
[Nilsson et al, Trans Veh Tech, submitted]
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 20
Model validation
• Since it is possible to import
GPS routes into SUMO,
one can simulate a scenario
with an implemented model
on a route for which we
have real measurements.
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 21
Current and future work
• With the presented framework it is possible to perform realistic cross-layer
geometry based simulations including:
– Cross-correlation between links,
– Autocorrelation for each link,
– Model validation.
• We will extend this to enable more realistic simulations of platooning scenarios.
• Integrating the control and communication systems for improved cooperative ITS.
• Implement intersection channel model in Veins.
Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November 2016. 22
References and contact information I
• Nilsson, Mikael, et al. “A Measurement Based Multilink Shadowing Model for
V2V Network Simulations of Highway Scenarios.” IEEE Transactions on
Vehicular Technology (Submitted).
• Abbas, Taimoor, et al. "A measurement based shadow fading model for vehicle-
to-vehicle network simulations." International Journal of Antennas and
Propagation 2015 (2015).
References and contact information II
• Segata, Michele, et al. "PLEXE: A Platooning Extension for Veins," Proceedings
of 6th IEEE Vehicular Networking Conference (VNC 2014), Paderborn, Germany,
December 2014.
• Varga, András. "The OMNeT++ discrete event simulation system."Proceedings of
the European simulation multiconference (ESM’2001). Vol. 9. No. S 185. sn,
2001.
• Christian Nelson
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