Energy-efficient and localization-based dynamic scheduling scheme for underwater acoustic sensor networks

Underwater acoustic sensor networks (UASNs) are vital for monitoring marine environments, but they face challenges such as high energy consumption, limited bandwidth, poor localization accuracy, and void hole issues. The proposed scheme addresses these challenges by optimizing energy usage, improving localization accuracy, and ensuring reliable communication through dynamic scheduling and void hole avoidance. This paper presents an energy-efficient and localization-based dynamic scheduling (EELDS) scheme for UASNs, designed to optimize energy consumption, enhance localization accuracy, and extend network lifetime in dynamic underwater environments. The proposed EELDS protocol integrates multiple localization techniques. The EELDS scheme utilizes localization techniques, including angle of arrival (AoA), time of arrival (ToA), time difference of arrival (TDoA), and received signal strength indicator (RSSI), to accurately estimate node positions. At the same time, the five-state model (FSM) (anchor, active, midway, idle, sleep) dynamically adjusts the network's energy consumption based on node states, optimising both energy efficiency and network performance. The scheme further incorporates void hole avoidance using relay nodes to ensure efficient data transmission in areas prone to communication voids. Results demonstrate that EELDS outperforms existing protocols by reducing energy consumption, extending network lifetime, and improving throughput, particularly in large-scale UASN deployments. Simulation results for 230 nodes over 5,000 rounds demonstrate that EELDS achieves a 27–35% longer network lifetime, 41–67% higher throughput, and a 30–50% lower energy-per-bit cost compared to MAC-layer schemes. Moreover, EELDS reduces localization error by 45–57%, improves connectivity by up to 33%, and decreases collisions by more than 50% compared with recent protocols. The results validate the effectiveness of EELDS in optimizing the operation of UASNs, making it a promising solution for real-world applications such as underwater exploration and oceanographic monitoring. • An energy-efficient localization-based dynamic scheduling (EELDS) scheme is introduced for UASNs. • Hybrid localization combining AoA, ToA, TDoA, and RSSI improves positioning precision. • A five-state adaptive energy model optimizes power usage across network operations. • Relay-assisted void hole handling ensures robust and uninterrupted data delivery.