Strategies for Context-Adaptive Message Dissemination in Vehicular Ad Hoc Networks

In future deployments of vehicular ad hoc networks (VANETs) safety-related applications such as local danger warning (LDW) will use broadcast-based communication schemes to transmit information to other vehicles within the network. The unlimited flooding of a message throughout the whole network however, is neither feasible nor intended. The high resulting traffic load would congest the shared wireless medium and prevent other, potentially highly relevant and time-critical messages from getting access to the medium. Existing strategies to limit redundant packet retransmissions manage to make broadcast-based data packet dissemination more efficient and reliable. However, they do not take into account the individual network's nodes interest in information. In fact, the static mechanisms proposed are not adequate to leverage the limited network resources as efficiently as possible in varying network conditions and to transport information to where it is needed as fast as possible. Therefore, we propose an altruistic communication scheme which differentiates data traffic according to the benefit it is likely to provide to potential recipients. A system for calculating and leveraging message benefit and two different node architectures are presented. With the help of a comprehensive simulation environment, the performance of our concept is analyzed. Comparative simulative studies show that an improvement of the benefit provided to all the participants in a VANET is also possible with the help of the readily available IEEE 802.11e standard, but to a lower extent.