3-D Trajectory Optimization for Fixed-Wing UAV-Enabled Wireless Network

Alessandro Visintini,Tharindu D Ponnimbaduge Perera,Dushantha Nalin K Jayakody

doi:10.1109/access.2021.3061163

Abstract

Unmanned aerial vehicles (UAVs) is a promising technology for the next-generation communication systems. In this article, a fixed-wing UAV is considered to enhance the connectivity for far-users at the coverage region of an overcrowded base station (BS). In particular, a three dimensions (3D) UAV trajectory is optimized to improve the overall energy efficiency of the communication system by considering the system throughput and the UAV’s energy consumption for a given finite time horizon. The solutions for the proposed optimization problem are derived by applying Lagrangian optimization and using an algorithm based on successive convex iteration techniques. Numerical results demonstrate that by optimizing the UAV’s trajectory in the 3D space, the proposed system design achieves significantly higher energy efficiency with the gain reaching up to $20\,\,bitsJ^{-1}$ compared to the $14\,\,bitsJ^{-1}$ maximum gain achieved by the 2D space trajectory. Further, results reveal that the proposed algorithm converge earlier in 3D space trajectory compare to the 2D space trajectory.

Highlights

Unmanned aerial vehicles (UAVs) has become an essential device in generation communications with significant contribution made in open literature using it to fulfil high data demands of mobile users [1]
The offset between EE3D and EE3lbD is due to the fact that the upper bound for the energy consumption equation is tight when the UAV trajectory is a steady circular flight
Next. a scenario with the UAV’s trajectory supposed to be circular is considered in which radius, height and velocity are optimized allowing the formulation of two semi-analytical solutions

Summary

INTRODUCTION

Unmanned aerial vehicles (UAVs) has become an essential device in generation communications with significant contribution made in open literature using it to fulfil high data demands of mobile users [1]. We study an energy efficient design for UAV assisted communication, where multiple UAVs are used to assist the base station during cell overload scenario over a finite time horizon In such a scenario, fixed-wing UAVs are used as relay nodes to assist information to the users who are in the boundary of the base station coverage area. Proposed energy-efficient trajectory design guarantees the balance between throughput maximization and UAV’s energy consumption minimization in 3D trajectory unlike the conventional 2D trajectory design found in open literature This is the first work in which the concept of energy efficiency have been proposed for multi UAV assisted overcrowded BS scenario using all the UAVs as relay nodes. In this work we are using a DF protocol, in order to have a reduced complexity in the optimization problem

UAV ENERGY CONSUMPTION MODEL

THREE DOF BOUNDED TRAJECTORY

CONSTRAINT AND BOUNDED THREE DOF TRAJECTORY

UNBOUNDED 3D TRAJECTORY

BENCHMARK

CONCLUSION