The Impacts of Node Orientation on Radio Propagation Models for Airborne-Deployed Sensor Networks in Large-Scale Tree Vegetation Terrains

In deterministic deployment of wireless sensor networks (WSNs), nodes are carefully placed at desired locations, with careful planning for separation distances, heights, and node orientations. This deployment strategy ensures good radio communication and sensing coverage. However, deterministic deployments are impractical for harsh large tree vegetation environments that span hundreds of kilometers. In these cases, stochastic deployments may enable effective deployment strategies. When relying on stochastic deployments, nodes are likely to be positioned at un-desired locations with unknown node orientations, which can lead to suboptimal radio connectivity and network performance. This paper examines the effects of factors affecting path loss under conditions resembling stochastic aerial deployments of WSN. Unlike previous work in the existing literature, this paper takes into account important deployment factors that affect network performance, such as node orientation and positioning, energy-to-bit-rate ratio, packet loss rate, and the composition of environment. Based on experimentation, a set of path loss models are proposed to model radio signal propagation in jungle-like environments under side-effects encountered in aerial deployments. The proposed models are compared with theoretical models and with other proposed models in the literature. Results show a significant difference with improved network performance that exhibits enhanced energy-to-bit-rate ratio, reduced packet loss rate, and increased node lifetime.