Disseminating Traffic Data over Vehicles on Road  A Preliminary Proposal to the ITA Demo Project Presented by Bo Xu

Outline Objective Demo Scenarios Possible Technical Approaches Steps Relevant Projects

Objective Build a demo system that enables disseminating traffic data over a fleet of vehicles, where traffic data includes –GPS locations of vehicles –Speeds of vehicles –Still images of traffic situation –Video clips of traffic situation The demo system serves as a seed into which other CTS research may be integrated

Demo Scenario 1: Disseminating GPS Locations and Speeds A fleet (e.g., 20) of vehicles drive along a highway. Each vehicle samples its location and speed periodically and disseminates them to the other vehicles in the fleet. Each vehicles reconstructs a global view of the fleet A B CD 54, , , , 1.2 speed distance

Demo Scenario 2: Disseminating Still Images Each vehicle takes pictures of the traffic ahead periodically and disseminates along with the location and speed information. Picture and speed provide better perception of traffic condition Picture taken by A A B CD 45 MPH 1.2 miles

Demo Scenario 3: Disseminating Video Clips Each vehicle shoots and disseminates the video of the traffic ahead Video shot by A A B CD 45 MPH 1.2 miles

Possible Technical Approaches Mobile Peer-to-peer (P2P) –Each vehicle is equipped with a short-range wireless device such as an enabled PDA. –Traffic data is transitively disseminated among vehicles –Being studied in our research A B CD Picture taken by A 45 MPH 1.2 miles

Mobile P2P Dissemination Two paradigms –Stateful A routing structure is imposed and maintained among vehicles May be ineffective in a highly mobile or partitionable environment –Stateless The intermediate vehicles save data and later (as new neighbors are discovered) transfer the data Also called stateless gossiping, epidemic, or store-and- forward dissemination

Mobile P2P Dissemination (Cont’d) Decisions to make at each vehicle –When to transmit Upon discovering new neighbors Upon receiving new data Periodic transmitting –How much to transmit Maximizing wireless throughput –What to transmit Ranking based on spatio-temporal relevance Adjustment: If two pieces of data pertain to vehicles close to each other, then only one piece needs to be transmitted Ranked Store-and-forward (studied in our ICDCS’06, ICWMC’07, MDM’07, TAAS papers)

Risk of Mobile P2P Can mobile P2P provide enough throughput for video transmission for multi- hops? –Existing study has shown that the throughput of mobile P2P networks decreases dramatically as the number of hops increases. –In our case, in order to see the real-time traffic condition one mile ahead, 16 hops are needed

Alternative: Central Server Solution Each vehicle transmits its video clips to a central server via the cellular infrastructure. The video clips are downloaded by other vehicles via the cellular infrastructure. ITA Server at UIC Video shot by A A B CD 45 MPH 1.2 miles

Steps Test with two pedestrians Test with a group of pedestrians. From this test we will know whether a mobile P2P network can provide enough throughput for video dissemination for multi-hops Test with two vehicles Test with a fleet of vehicles

Collecting Empirical Data Use the demo system to generate traces of vehicles and to collect empirical data about inter-vehicle communication. –What is the transmission range of in a highway environment –What is the wireless capacity and how it depends on the speed and density of the communicating vehicles as well as their transmission size and frequency –The vehicle traces and the empirical data can be used as a simulation test-bed for our future study on vehicular networks.

Devices Camera phone GPS Interface with vehicle on-board computer –OBD (On-Board Diagnostics) –Obtain speed, brake position, ABS, fuel pressure, throttle position

Relevant Projects Three types of applications that involve inter-vehicle communication –Information and warning functions Dissemination of road information (including incidents, congestion, surface condition, etc.) to vehicles distant from the subjected site. Our demo project mainly belongs to this type –Communication-based longitudinal control Exploiting the “look-through” capability of IVC to help avoiding accidents and platooning vehicles for improving road capacity. –Co-operative assistance systems Coordinating vehicles at critical points such as blind crossings (a crossing without light control) and highway entries

Information and warning functions No real system implemented yet Grassroots, Rutgers University, disseminating travel time Collaborative Content Distribution for Vehicular Ad Hoc Networks, UCBerkely –Propagating data along a highway using the network coding technique –Comparison/integrating with ranked store-and-forward? Problem: An infostation is disseminating data to all the vehicles that are traveling in the same direction along the highway

Communication-based longitudinal control TrafficView, Rutgers University, –Exchange GPS locations/speeds among vehicles – based –Demo with 4 vehicles seemly within a single hop –Demo video available at

Co-operative assistance systems CPF (Collaborative Perception Framework), INRIA, France –Sensor fusion to determine orientation and location of a vehicle Speedometer, Gyrometer (angular speed), GPS – based –Demo with 2 vehicles and one roadside facility within a single hop –Demo video 1Demo video 1 –Demo video 2Demo video 2

Questions/Comments? Question: How do you see your research integrating into the proposed seed- ITA?