1. A Structure-free Aggregation Framework for Vehicular Ad Hoc Networks Stefan Dietzel, Elmar Schoch, Boto Bako, Frank Kargl

2. Outline Introduction and Contribution Motivation Fuzzy Reasoning System System Architecture Simulation Results

3. Introduction and Contribution Data Aggregation in VANET The challenge of aggregation lies in the proper decision if two single data items should be aggregated or not. Contribution It is not necessary to define aggregate structures such as hierarchical grids or fixed road segments or to establish a processing structure like a hierarchy or a group of nodes.

4. Motivation: DA in WSN not suitable In a highly dynamic network like VANETs, building such hierarchies is not feasible or would at least result in high communication overhead. VANET applications like collaborative detection and dissemination of traffic congestions require periodic status information over road conditions in order to work properly. Drawbacks of pre-defined aggregation structure: This requires that vehicles have a common knowledge about the road network and its segmentation which is problematic regarding the variety of VANET applications.

5. A reduction of the information accuracy with increasing distance is not always an appropriate solution.

6. Fuzzy Set Systems

8. System Architecture

9. Simulation