Study on a Novel Architecture for Marine Internet of Things Based on Ultrasonic BackCom-SWIPT

Owing to the low attenuation of sound waves underwater, simultaneous wireless information and power transfer (SWIPT) via ultrasonic means can enable sustainable and large-scale marine Internet of Things (MIoT) systems in underwater environments. Backscatter communication (BackCom) has remarkable potential in passive underwater acoustic communications for its superb low-power characteristics. However, challenges persist in powering acoustic transmitting transducers in underwater environments. In this study, we propose a novel MIoT architecture based on ultrasonic SWIPT with BackCom (BackCom-SWIPT), which relies on self-powered MIoT passive nodes (MIoT-PNs) capable of both energy harvesting (EH) and BackCom. Based on transducer model and differential backscatter wave (DBW) theories, the impacts of electrical load impedance of MIoT-PNs on DBW and EH are validated through simulations and experiments. The proposed ultrasonic BackCom-SWIPT system is further validated in both static and dynamic MIoT scenarios. Passive sensing information acquisition is achieved based on a seafloor observation network (SON) unit of MIoT, with a bit error rate less than 0.01. In addition, passive localization and navigation are conducted on an underwater vehicle (UV), with a communication throughput of 1 kbps. The proposed approach addresses the issue of high-power electrical supply for transmitting transducers, and low-power uplink (UL) communication in underwater settings, laying the groundwork for the large-scale deployment of MIoT with passive nodes.