Altitude Range and Throughput Analysis for Directional UAV-assisted Backscatter Communications Networks

In the realm of Internet of Things (IoT) networks, Backscatter communication (BackCom) is a promising technique that allows devices to send data through the reflecting surrounding radio frequency (RF) signals. Integrating unmanned aerial vehicles (UAVs) with BackCom technology to establish UAV-assisted BackCom networks presents an opportunity to provide self-generated RF signals for backscatter devices, establishing self-sustaining data collection systems. This paper investigates directional UAV-assisted BackCom networks where UAVs are equipped with directional antennas, which differs from previous studies that mainly consider omni-directional antennas. To ensure the quality of BackCom, we develop a theoretical model that analyzes the valid altitude range of UAVs, which is often ignored in previous studies. Based on the altitude range of UAVs, we then derive the throughput of directional UAV-assisted BackCom networks. Extensive simulations are conducted to verify our theoretical model, revealing correlations between the UAV altitude range, the throughput, directional antennas, and other key parameters. Results indicate that UAVs need to set the proper UAV altitude according to multiple parameters to ensure successful communication. In addition, adjusting the beamwidth of directional antennas can enhance both the altitude range of UAVs and the throughput of networks.