Autonomous Underwater Vehicle–Enabled Data Collection for Underwater Wireless Sensor Networks: A Systematic Taxonomy, Protocol Review, and Open Challenges

Autonomous Underwater Vehicles (AUVs) have emerged as an effective solution for data collection in Underwater Wireless Sensor Networks (UWSNs), addressing fundamental limitations of acoustic communication such as limited bandwidth, long propagation delays, and high error rates. By moving close to each sensor node for direct data retrieval, AUVs improve energy balance, extend network lifetime, and enhance coverage flexibility. However, AUV-assisted data collection introduces complex challenges, including trajectory optimization under energy, latency, and coverage constraints, as well as robustness to dynamic ocean environments, intermittent connectivity, and large-scale multi-AUV coordination. This survey presents a systematic review of 56 representative AUV-assisted data gathering protocols (2011–2025) and introduces a unified six-class taxonomy that consolidates fragmented classifications in the literature. Following a structured screening of more than 200 peer-reviewed records, these 56 protocols were selected for detailed taxonomy-based analysis. The proposed taxonomy spans classical trajectory optimization, clustering-based organization, learning-based single-AUV methods, multi-AUV coordination, hybrid communication and quality-aware strategies, and energy and lifetime management. In addition, we provide a comparative analysis across key performance dimensions, including energy efficiency, network lifetime, latency, Age of Information (AoI), delivery reliability, and scalability, highlighting fundamental trade-offs among these metrics. Our analysis reveals a clear shift toward learning-based and AoI-driven approaches, while identifying critical gaps in real-world validation, scalability of multi-AUV systems, and security-aware cross-layer design. Finally, we outline open research challenges and future directions to guide the development of robust, scalable, and deployable AUV-assisted data collection systems for next-generation ocean monitoring applications.