Energy-Efficient Routing Approaches in FANETs: An Extensive Survey

Flying Ad-hoc Networks (FANETs) enable multi-hop wireless Unmanned Aerial Vehicles (UAVs) to connect for information dissemination, eliminating the need for specialised infrastructure. However, the limited battery power of UAVs is a significant challenge in FANETs, as efficient energy utilisation is required in routing. Additionally, network performance suffers since UAVs lose contact with one another as their batteries die in any critical mission. Therefore, FANETs require an effective routing technique that optimises energy consumption. Considering this important issue, this extensive survey provides an in-depth explanation of state-of-the-art Energy-efficient Routing (EeR) approaches in FANETs from 2018 to 2024. In this survey, 72 research papers were selected from the Scopus database using predefined inclusion and exclusion criteria, study selection, and execution steps. The survey discussed in detail to identify the energy-aware metrics, their working processes and contributions, and to examine their performance metrics, comparative analyses, advantages, and limitations. Further, identify typical challenges and suggest potential research paths in the domain that can leverage the full potential of efficient routing. The main objective of this study is to assist ad-hoc network engineers, researchers, and application developers working in the field of FANETs in the process of selecting acceptable routing protocols that are efficient in terms of energy consumption.