# An Experimental Tethered UAV-Based Communication System with Continuous Power Supply
## 1 Introduction
Recent research proposes several solutions, including renewable energy, wireless charging, and battery swapping. The most widely used method is battery replacement, which involves the UAV making constant trips to place a charged battery [10]. However, this process must be carried out accurately to avoid service interruptions. Additionally, the need for multiple batteries and swapping stations can lead to increased operational and logistical costs. One promising alternative is tethered unmanned aerial vehicles (T-UAVs), which provide a constant power supply, reduce battery dependency, enable continuous and stable data transmission, and offer greater security against UAV downtime. This paper addresses the design and implementation of a power network that ensures the extended operation of the UAV, as well as the development of a communication system based on a T-UAV, offering a unified communication system. The importance of this study lies in ensuring an uninterrupted communication service, which involves solving the problem of flight duration. In recent years, research has focused on reducing one of the primary limitations of UAV deployment, i.e., energy consumption. Traditional UAVs are based on a battery inside, usually allowing flight times between 20 and 40 min, depending on the size, payload, and environmental conditions [8]. Several studies have investigated strategies to address energy constraints. [PERSON] et al. [11] proposed a hierarchical real-time control strategy for UAVs that aims to minimize energy consumption while maintaining low computational complexity. This approach is grounded in optimal control theory but translates theoretical trajectories into implementable, rule-based references. Their solution achieves near-optimal energy use levels while remaining feasible for on-board real-time implementation. This work highlights the value of mission planning, trajectory smoothing, and reference generation to improve UAV energy efficiency. Similarly, [PERSON] et al. [12] explore energy-efficient communication architectures, focusing on the integration of UAVs into next-generation networks. The study highlights the energy trade-offs associated with different communication modes and proposes solutions, including cooperative relaying and T-UAVs. These systems, powered from the ground, allow continuous operation and eliminate battery limitations, offering a viable solution for scenarios requiring prolonged coverage. Despite growing attention to energy management in UAVs, few works have explored integrated solutions that combine trajectory optimization and real-time communication support. To improve the contextual understanding of UAV communication, we consider the work of [PERSON] et al. [13] that proposes a two-layer encryption protocol for the secure transmission of military reconnaissance images over UAV-assisted relay networks. Their solution addresses the need for robust and secure communication in hostile or unpredictable environments, integrating genetic algorithms and DNA coding with low-density parity-coded-based transmission schemes. In addition, differences in control and autonomy levels between UAV platforms, particularly in reconnaissance applications, introduce operational complexities. As noted by [PERSON] et al. [14], the integration of UAVs into unmanned ground vehicle systems improves terrain analysis and mission adaptability in unknown environments. Their work highlights the role of UAVs in supporting decision making for autonomous ground systems, emphasizing the challenges of coordination and real-time data exchange that must be considered in integrated mission planning. Finally, [PERSON] et al. [15] present a comprehensive review of the widely used protocols, Wi-Fi, Zigbee, and LoRaWAN, detailing their respective strengths and limitations in UAV scenarios. Their findings reveal necessary trade-offs in range, data rate, power consumption, and security, which must be considered when selecting communication technologies for UAV deployments.