Abstract
This paper addresses the design of hybrid free-space optical/radio frequency (FSO/RF) systems for a high-altitude platform (HAP)-aided relaying satellite communication for mobile networks supported by unmanned aerial vehicle (UAV). While prior work primarily focused on fixed-rate design, which frequently switches between FSO and RF lead reduced the system performance, we propose a rate adaptation design that gradually adjusts the data rate in each link when its channel state fluctuates, under a target bit error rate (BER) constraint. The proposed design’s downlink performance is analyzed, taking into account many challenging issues, including beam spreading loss, cloud attenuation, statistical behaviors of the atmospheric turbulence in the dual-hop channel, and pointing misalignment due to the UAV hovering. Different performance metrics are analytically derived based on channel modelings, including outage probability, average transmission rate, and achievable spectrum efficiency. In addition, the average system BER, which satisfies the design constraint, is also numerically obtained. The results quantitatively confirm the effectiveness of our proposed system under the impact of UAV hovering misalignment and atmospheric-related issues like clouds and turbulence. Finally, Monte-Carlo simulations validate the accuracy of theoretical results.
Highlights
According to the International Telecommunication Union (ITU) report in 2019, half of the world population did not have regular Internet access [1]
We propose a multi-rate design for the integrated downlink satellite-high-altitude platform (HAP)-unmanned aerial vehicle (UAV) with the help of hybrid freespace optical/radio frequency (FSO/RF) systems to counteract the effect of transmission media
We highlight the effectiveness of our proposed systems by comparing performance metrics analyzed in Section IV with those of conventional systems, i.e., adaptive dual-hop free-space optical (FSO)-FSO, adaptive dual-hop FSO-RF, and fixedrate dual-hop FSO-hybrid FSO/RF designs
Summary
According to the International Telecommunication Union (ITU) report in 2019, half of the world population did not have regular Internet access [1]. In [15], the authors studied the downlink satellite-HAP-ground with the assumption of gamma-gamma turbulence channel model for FSO link and Rician distribution for RF link. The combined channel model for the FSO link was taken into account free space loss, atmospheric turbulence, and beam wander induced pointing error. In both [15], [16], the single-threshold-based scheme was used to switch between RF and FSO links. We propose a multi-rate design for the integrated downlink satellite-HAP-UAV with the help of hybrid FSO/RF systems to counteract the effect of transmission media.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
