A Simulation Framework for V2V Wireless Systems

Transcription

1 A Simulation Framework for V2V Wireless Systems CHRISTIAN 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

2 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

3 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

4 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 In early ITS, these technologies will have to coexist. 1 ericsson.com, LTE for Intelligent Transport Systems, June 9, Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November

5 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

6 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

7 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

8 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

9 Simulation Framework Summary Plexe-Veins MAC Layer PHY Layer Mobility Interface Plexe-SUMO Road Traffic Simulation OMNeT++ / OMNEST Inspired by Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November

10 V2V System Simulation Framework OMNeT++ - Discrete Event Simulator, ( Veins - Vehicles in Network Simulation, ( Sumo - Simulation of Urban Mobility, ( Plexe - Platooning Extension for Veins, ( Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November

11 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

12 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

13 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

14 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

15 Simulation Framework Summary Plexe-Veins MAC Layer PHY Layer Mobility Interface Plexe-SUMO Road Traffic Simulation OMNeT++ / OMNEST Inspired by Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November

16 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

17 Two-ray and single-slope pathloss models Two-ray LOS Single-slope OLOS [Nilsson et al, Trans Veh Tech, submitted] Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November

18 Two-ray pathloss model [Nilsson et al, Trans Veh Tech, submitted] Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November

19 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 t Τ T c Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November

20 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

21 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

22 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

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24 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 vehicleto-vehicle network simulations." International Journal of Antennas and Propagation 2015 (2015).

25 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 Varga, András. "The OMNeT++ discrete event simulation system."proceedings of the European simulation multiconference (ESM 2001). Vol. 9. No. S 185. sn, Christian Nelson christian.nelson@eit.lth.se Christian Nelson, IEEE VTS Workshop on Wireless Vehicular Communications, November