Impact of transmission power on safety message communication under sparse vehicular ad hoc networks

Transmission power is an important determinant of the performance of Vehicular Ad Hoc Networks (VANETs) due to its direct influence on the reliability and efficiency of safety message communication in both vehicle-to-vehicle and vehicle-to-roadside unit encounters. Vehicular mobility-induced dynamic topology makes it difficult to maintain stable connectivity, especially in sparse and intermittently connected network environments. As a result, resorting to fixed transmission power levels leads to network performance and connectivity degradation. This paper presents a novel model for connectivity assessment that aims to study the effect of varying transmission power levels under various VANET scenarios. The model evaluates network performance across multiple transmission power configurations and traffic densities using key efficacy metrics, including connectivity stability, communication overhead, latency, and safety message delivery performance. The results demonstrate that inappropriate transmission power selection negatively affects VANET connectivity by increasing channel contention in dense regions and significantly reducing communication reliability in sparse and void areas.