Performance of UAV-to-Ground FSO Communications with APD and Pointing Errors

Ha Trung

doi:10.3390/asi4030065

Abstract

Recently, a combination of unmanned aerial vehicles (UAVs) and free-space optics (FSO) has been investigated as a potential method for high data-rate front-haul communication links. The aim of this work was to address the performance of UAV-to-ground station-based FSO communications in terms of the symbol error rate (SER). The system proposes utilizing subcarrier intensity modulation and an avalanche photo-diode (APD) to combat the joint effects of atmospheric turbulence conditions and pointing error due to the UAV’s fluctuations. In the proposed system model, the FSO transmitter (Tx) is mounted on the UAV flying over the monitoring area, whereas the FSO receiver (Rx) is placed on either the ground or top of a high building. Unlike previous works related to this topic, we considered combined channel parameters that affect the system performance such as transmitted power, link loss, various atmospheric turbulence conditions, pointing error loss, and the total noise at the APD receiver. Numerical results have shown that, for the best system SER performance, the value of an average APD gain at the Rx can be selected, varying from 18 to 30, whereas the equivalent beam waist radius at the Tx should be in a range from 2 to 2.2 cm in order to decrease the effects from the UAV’s fluctuations.

Highlights

Unmanned aerial vehicles (UAVs), known as drones, were mainly used in the military field
We provide numerical results in terms of symbol error rate (SER) to analyze the performance of the unmanned aerial vehicles (UAVs)-to-ground free-space optics (FSO) communication system with avalanche photo-diode (APD) and pointing errors under the influence of various operating conditions
We considered using one UAV, under the assumption that the UAV hovers over a specific monitoring area to collect measured data from sensors on the ground

Summary

Introduction

Unmanned aerial vehicles (UAVs), known as drones, were mainly used in the military field. A UAV can move to complex locations or notify areas that may pose danger to humans, and move steadily over the desired area to act as a relay node for communication cooperation between ground nodes and a central point (CP) [4,5]. In these cases, free-space optical (FSO) communications, a cost-effective, license-free, easy-to-deploy, high-bandwidth, and secure access technique, is being viewed as a potential candidate for the front-hauling transmission of multimedia data collected by flying

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Conclusion