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In multi-hop dissemination a timer-based and a probabilistic methods are the high performing methods in Vehicular Ad-hoc Networks (VANETs), due to simplicity, low overhead, and high efficiency. However, such approaches neglect the fact that vehicles transmission ranges are typically heterogeneous due to different transmission power values. In our previous work, we introduce new area-based methods for heterogeneous transmission ranges in vehicle networks, i.e. Area Defer Transmission (ADT), Area-based Probabilistic Transmission (APT), and an integration of area-based timer and probabilistic transmission methods. ADT proves it efficiency over distance-based methods, and the probabilistic version due to high delivery ratio, high propagation speed and reachability. The work is extended and we introduce an enhancement of ADT defer time formula. The enhancement gives vehicles with larger potential coverage area high opportunity to relay the message than the one with small potential coverage area or small communication range. The performance of the proposed enhancement is compared to ADT and evaluated using an actual road map with complex road scenarios and real movement traces. The simulation results show that the dissemination speed improves dramatically, with better saved-retransmission and delivery ratio. |
