Air-Aided Communication Between Ground Assets in a Poisson Forest

TL;DR

This paper develops an analytical model to compute the probability of line-of-sight communication between ground and air assets in a forest environment, considering obstacle heights and optimizing relay deployment for improved throughput.

Contribution

It introduces a novel inhomogeneous Poisson process model for LoS probability in a forest, including closed-form expressions and validation, and analyzes optimal relay positioning and height for communication.

Findings

LoS probability depends on obstacle height distribution and distance.

Optimal air asset height maximizes end-to-end throughput.

Relaying is beneficial beyond certain communication distances.

Abstract

Ground assets deployed in a cluttered environment with randomized obstacles (e.g., a forest) may experience line of sight (LoS) obstruction due to those obstacles. Air assets can be deployed in the vicinity to aid the communication by establishing two-hop paths between the ground assets. Obstacles that are taller than a position-dependent critical height may still obstruct the LoS between a ground asset and an air asset. In this paper, we provide an analytical framework for computing the probability of obtaining a LoS path in a Poisson forest. Given the locations and heights of a ground asset and an air asset, we establish the critical height, which is a function of distance. To account for this dependence on distance, the blocking is modeled as an inhomogenous Poisson point process, and the LoS probability is its void probability. Examples and closed-form expressions are provided for two obstruction height distributions: uniform and truncated Gaussian. The examples are validated through simulation. Additionally, the end-to-end throughput is determined and shown to be a metric that balances communication distance with the impact of LoS blockage. Throughput is used to determine the range at which it is better to relay communications through the air asset, and, when the air asset is deployed, its optimal height.