Implementation of multi-UAV communication relay function based on mobile telecommunication technology

(2025) 2025:19 Tsai and Huang J Wireless Com Network https://doi.org/10.1186/s13638-025-02447-y EURASIP Journal on Wireless Communications and Networking Open Access RESEARCH Implementation of multi‑UAV communication relay function based on mobile telecommunication technology Wen‑Chung Tsai1* and Nien‑Ting Huang2 *Correspondence: 1 College of Information and Distribution Science, National Taichung University of Science and Technology, Taichung 404336, Taiwan, R.O.C. 2 Department of Cellular Application, Arcadyan Technology Corporation, Hsinchu 300044, Taiwan, R.O.C. Abstract This paper presents a Medium Access Control (MAC) functionality design for Unmanned Aerial Vehicle (UAV) relay transmission. In contrast to existing relay designs, this work proposes a relay transmission framework based on 3GPP communi‑ cation protocols. The core innovation lies in the introduction of an internal link channel within the Layer-2 MAC, enabling integration of Base Station (BS) and User Equipment (UE) functionalities within a single UAV communication module. The proposed Layer-2 MAC design is implemented within a System on a Programmable Chip, integrating both BS and UE functionalities into a unified platform. This modular approach allows future updates to BS and UE designs in line with evolving 3GPP standards by modifying only the relevant Intellectual Property (IP) components. Consequently, UAVs can effi‑ ciently support new communication standards while leveraging the reliability and sta‑ bility of commercially validated mobile communication technologies. The proposed design methodology capitalizes on mature mobile telecommunication frameworks to achieve high data throughput and low latency, ensuring real-time and reliable UAV communication. This paper details the relay transmission architecture, platform imple‑ mentation, and simulation environment, presenting experimental results that evaluate relay functionality and priority-based transmission performance. Keywords: Unmanned aircraft vehicle, Mobile telecommunication, Relay communication, Simulation environment, System on a Programmable Chip 1 Introduction This paper presents a design for multi-UAV relay transmission, validated using a custom-developed communication simulation environment. While wireless communication for Beyond-Visual-Range (BVR) control has been established for some time, ongoing debates focus on the pros and cons of Unmanned Aerial Vehicle (UAV) communication systems, such as cost, flight range, and transmission capabilities. Key considerations include whether to rely on existing commercial networks, build custom infrastructure, or develop proprietary protocols. The fourth-generation (4G) mobile telecommunication standard, represented by Long Term Evolution (LTE), provides extended signal range and, as defined by the © The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/. Tsai and Huang J Wireless Com Network (2025) 2025:19 International Telecommunication Union Radiocommunication Sector (ITU-R), achieves data transmission speeds of at least 100 Mbps in high-mobility conditions (120 km/h to 350 km/h) with 20 MHz bandwidth. Currently, fifth-generation (5G) technology offers even greater capabilities: at low frequencies (< 3 GHz), it supports up to 50 MHz bandwidth with speeds of 0.3 Gbps, at mid frequencies (3–6 GHz), 100 MHz bandwidth with speeds of 1–3 Gbps, and at extremely high frequencies (mmWave, > 24 GHz), up to 400 MHz bandwidth with transmission speeds exceeding 10 Gbps. [1] Given the design and development capabilities for 4G/5G-related products, including both BS and UE, in terms of software and hardware in developing a mobile telecommunication system, this paper proposes a multi-UAV relay transmission design based on the existing mature protocol frameworks provided by 3rd Generation Partnership Project (3GPP) [2]. This design allows multiple UAVs with relay capabilities to transmit datagrams to the farthest UAV, enabling UAVs to reach previously inaccessible but critical areas for exploration, observation, and data collection. The collected data can be immediately transmitted back to the ground console station, facilitating real-time decision-making and response. This functionality is particularly applicable to UAV operations requiring long-distance or complex environmental navigation, such as search and rescue missions, disaster monitoring, or wide-area surveillance [3]. Accordingly, this paper presents a versatile, portable, and scalable scheduling framework designed for diverse communication technologies in wireless environments [4, 5]. The framework proposes a scheduling and task allocation method that meets the quality of service (QoS) requirements of downlink (DL) and uplink (UL) data transmissions for the Layer-2 MAC protocols of both BS and UE [4]. To meet the computational complexity and scheduling performance demands BS, the framework considers aspects such as bandwidth allocation, data scheduling, and channel management. The scheduling algorithm is designed based on parameters like the size of data payload, urgency, and wireless conditions, as well as the Guaranteed Bit Rate (GBR) and Non-GBR bandwidth configurations set during the establishment of wireless bearers. This allows the efficient allocation of the required bandwidth for DL and UL transmissions, ensuring QoS for data transmission as defined in 3GPP Release 18 (Table 6.1.7-A: Standardized QCI characteristics of 3GPP TS 23.203 [6]). The key innovation of this work is the integration of the Layer-2 MAC design [7] for both the BS and an UE using System on a Programmable Chip (SOPC) Builder [8], eliminating the need for separate devices or distinct chips for BS and UE functions on the UAV. This approach builds on existing mobile telecommunication capabilities defined by 3GPP [2], requiring only minor modifications to the Layer-2 MAC to enable relay transmission of MAC Protocol Data Units (PDUs). In essence, the proposed method of directly integrating (...truncated)