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Simulator integration:Vissim (Environment simulator) +
NS2 (Telecom simulator) =
RuBeNS Rural & UrBan e-Travelling Network Simulator
Péter Laborczi
Sándor Kardos
Attila Török
Lóránt Vajda
Main goal
Integrate environment simulator with telecommunications simulator to evaluate protocols for specific scenarios
1. Pile-up avoidance scenario (accident prevention)
2. Road traffic information scenario (traffic jam avoidance)
3. Ad hoc tempomat scenario (driving comfort)
Example
Floating Car Data:
• Vehicle act as moving sensors
- GPS
- Weather sensors
- Radar
Distributed
Centralized
Emergency signalling implementation
Purpose:
• Test the effects of wireless emergency warning signalling
Why?
• If legal restrictions forbid intervention (breaking), only signalling is possible
Implemented signalling
• Vehicle detecting accidents broadcasts warning message
• Messages are forwarded up to 1000m by cars
• Equipped car drivers are notified when the message is received
• Cars with no warning device notice the problem 1.5 seconds after the supposed reception
Ad hoc traffic information sending/handling
Purpose:
• To avoid traffic jams without centralinfrastructure
Why?
• Reduce travel times withouta single point of failure and maintainance costs
Implemented signalling
• Equipped cars send travel time information
• They receive information for all neighboringstreets
• Based on this information they reroute whennecessary
GPS module
Purpose:
• Realistic modelling of GPS errors
Why?
• Crucial to prevent bump-ins
Error sources and modelled error [m]:
Error source GPS DGPS
Satellite Clocks 1.5 0
Orbit errors 2.5 0
Ionosphere 5 0.4
Troposhere 0.5 0.2
Receiver noise 0.3 0.3
Multipath 0.6 0.6
Graph representation of road network
Purpose:
• To have a mathematically tractablemodel of the map
Why?
• To be able to find shortest path (Dijkstra)between locations and be able to selectrelevant messages
Implementation of an online ”converter”from Vissim road network format to our(Boost library based) graph format
Realworld map converter
Purpose:
• Convert XML format mapfile to VISSIM format
Why?
• To be able to simulatetraffic in real cities
Part of Budapest (BUTE surroundings) can nowbe examined within RuBeNS
Danube
Kalvin sqare
BUTE surroundings
XML based traffic matrix handling
Purpose:
• To have an easily usable trafficdescription
Why?
• To be able to examine differenttraffic conditions
Implementation is based on xmlwrapp library
Vehicular communication systems - Software Modules
VISSIMRoad traffic simulator
VISSIM interface
TCP/IP Socket
NS-2
TCP/IP Socket
PHY
CommunicationProtocol
Application / Group comm.
interface
interface
WindowsLinux
Four Scenarios
1. Traditional see the DEMO
• No equipped vehicles
2. Centralized FCD
3. Distributed FCD see the DEMO
• Ad-hoc route guidance
4. Cooperative route guidance see the DEMO
Average Travel Time
Traditional scenario Centralized FCD Distributed FCDCooperative Route
Guidance
Average travel time 386.5 sec 164.2 sec 156.8 sec 114.2 sec
Route travel times
Lookout
Simulation environment RUBeNS implemented to simulate:
• Road network & vehicle traffic
• Infocommunication network & data traffic
Different FCD approaches and communications simulated
More applications are under development:
• Ad-hoc tempomat (ACC)
• pile-up avoidance
• Intelligent flooding protocol
Study of the communication network:
• Load
• Latency
• Reliability
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