A Generalized Pointing Error Model for FSO Links with Fixed-Wing UAVs for 6G: Analysis and Trajectory Optimization

TL;DR

This paper introduces a comprehensive 3D pointing error model for UAV-based FSO links in 6G networks, enabling optimized trajectories that significantly improve energy efficiency by accounting for UAV jitter effects.

Contribution

It presents a novel 3D jitter-based pointing error model for UAV FSO links and integrates it into a trajectory optimization framework for enhanced energy efficiency.

Findings

Optimized UAV trajectories increase energy efficiency by up to 11.8%.

The new model provides more accurate performance assessments for UAV FSO links.

Trajectory optimization considering 3D jitter outperforms conventional models.

Abstract

Free-space optical (FSO) communication is a promising solution to support wireless backhaul links in emerging 6G non-terrestrial networks. At the link level, pointing errors in FSO links can significantly impact capacity, making accurate modeling of these errors essential for both assessing and enhancing communication performance. In this paper, we introduce a novel model for FSO pointing errors in unmanned aerial vehicles (UAVs) that incorporates three-dimensional (3D) jitter, including roll, pitch, and yaw angle jittering. We derive a probability density function for the pointing error angle based on the relative position and posture of the UAV to the ground station. This model is then integrated into a trajectory optimization problem designed to maximize energy efficiency while meeting constraints on speed, acceleration, and elevation angle. Our proposed optimization method significantly improves energy efficiency by adjusting the UAV's flight trajectory to minimize exposure to directions highly affected by jitter. The simulation results emphasize the importance of using UAV-specific 3D jitter models in achieving accurate performance measurements and effective system optimization in FSO communication networks. Utilizing our generalized model, the optimized trajectories achieve up to 11.8 percent higher energy efficiency compared to those derived from conventional Gaussian pointing error models.