Accurate localization of underwater sensor nodes is a fundamental yet challenging problem in underwater wireless sensor networks. Localization performance is severely affected by complex environmental factors, including measurement noise, Non-Line-Of-Sight (NLOS) propagation, absorption loss, and path attenuation. To address these challenges, this paper proposes an efficient and scalable localization mechanism based on Received Signal Strength Difference (RSSD). First, the Expectation–Maximization (EM) algorithm is applied to identify NLOS links and estimate their corresponding biases. Then, a weighted Huber loss function combined with an adaptive weighting strategy is introduced to construct an Adaptive Weighted Loss Function, which suppresses noise, adaptively reduces the influence of NLOS paths, and compensates residual biases. Based on this formulation, the localization task is transformed into an optimization problem. Furthermore, an improved Grey Wolf Optimizer (IGWO) incorporating an Adaptive Convergence Factor (ACF) and an Elite-Guided (EG) strategy is developed to enhance global search capability and convergence stability. Extensive simulation results demonstrate that the proposed method achieves significantly higher localization accuracy than existing approaches.

Online Fountain Codes (OFCs) adapt their encoding strategy to decoder feedback, making them attractive for Underwater Acoustic Sensor Networks (UASNs) with stringent delay and energy constraints. Yet, conventional OFCs perform poorly under the harsh conditions of UASNs, where high error rates, long propagation delays, and limited feedback severely restrict efficiency. This work identifies two key challenges: balancing recovery efficiency with intermediate decoding, and reducing encoding and decoding complexity under sparse feedback. To address them, we propose a Dual-Perception Fountain Code framework based on Deep Reinforcement Learning (DRL-OFC). A DRL agent learns optimized degree distributions to reduce redundant packets and improve decoding, while a feedback-aware strategy adapts transmissions to UASNs conditions. Simulations show that DRL-OFC achieves lower overhead, stronger intermediate recovery, fewer coded packets, and better energy efficiency than existing OFC schemes, confirming its suitability for resource-constrained underwater networks.

To address the pressing demands of marine resource exploration, this paper investigates the problem of node localization in underwater acoustic wireless networks and proposes a two-stage progressive collaborative optimization framework to overcome the performance limitations of the traditional DV-Hop algorithm. Error sources of DV-Hop in underwater scenarios are systematically analyzed, and a quantitative localization model, NSGA-II-DV-Hop, is established to incorporate both hop count estimation errors and position calculation errors. Based on this analysis, a two-stage optimization strategy is developed. In the first stage, an adaptive particle swarm optimization model, PSO-DV-Hop, is designed, where a dynamic inertia weight adjustment mechanism enhances global search efficiency, thereby reducing localization error and energy consumption. In the second stage, a Pareto-Based evolutionary optimization model, NSGA-II-DV-Hop, is introduced to realize simultaneous optimization of localization accuracy and energy efficiency through Pareto frontier analysis. Experimental results demonstrate that PSO-DV-Hop improves localization performance by reducing the average error by 18.2% and lowering the number of convergence iterations by 61%. Building on this, NSGA-II-DV-Hop further extends the network lifetime by 26.9%, reduces average node energy consumption by 10.07%, and achieves an additional 8.67% energy optimization.

Underwater Wireless Sensor Networks (UWSNs) are integral to marine exploration yet confront significant security concerns. In contrast to terrestrial WSNs, underwater acoustic channels are characterized by their constrained bandwidth, considerable propagation delays, and a higher bit error rate. These factors facilitate adversaries’ ability to intercept network transmissions and acquire sensitive data. Furthermore, the constraints of energy resources in UWSNs pose additional challenges in harmonizing privacy preservation with energy conservation. This study introduces a novel Privacy-Preserving Data Fusion Algorithm (DSPDA) tailored for UWSNs. The DSPDA circumvents the shortcomings of conventional privacy algorithms by employing dynamic sharding to minimize transmission demands and augment data fusion precision, which adjusts the size of data shards relative to nodal distances, thereby safeguarding confidentiality. Furthermore, it enhances network-wide energy optimization by aligning the energy consumption of cluster heads with their respective child nodes, thus averting disproportionate energy depletion and potential network dysfunction. Our simulation results demonstrate that the DSPDA algorithm notably diminishes communication overhead by approximately 37% in comparison to the SMART algorithm and delivers a further 20% efficiency improvement over the EEHA algorithm.

The burgeoning deployment of Underwater Acoustic Sensor Networks (UASNs) for maritime applications highlights the critical need for reliable trust models to defend against internal security threats. Existing trust models are often inadequate due to high packet error rates inherent in underwater communication and a lack of accounting for nodes' traffic behavior. Additionally, conventional UASN architectures suffer from significant latency in gathering and processing trust evidence, which delays the identification of adversarial nodes. Addressing these limitations, this paper proposes the Traffic-Aware and Edge Computing-Enabled Trust Model (TECTM), a solution expressly conceived for UASNs. TECTM integrates environmental models to assess the acoustic environment's impact on communication and employs network traffic analysis as a trustworthy metric for identifying attack patterns. Autonomous Underwater Vehicles (AUVs) serve as edge computing nodes, leveraging a machine learning algorithm to enhance trust assessments within node clusters. Moreover, TECTM introduces a refined trust update mechanism, designed to be responsive to the dynamic underwater environment and complex attack behaviors. Through comparative simulations, TECTM demonstrates enhanced accuracy in the detection of malicious nodes, outperforming other methods.

Underwater bionic covert communication technology is a novel means of hiding underwater information. In order to realize hydroacoustic bionic stealth communication, this paper proposes an underwater bionic stealth communication scheme based on humpback whale tick signal grouping combination coding. The scheme constructs a bionic stealth communication sequence based on the time-frequency characteristics, autocorrelation characteristics and distribution characteristics of the individual tick signals in the humpback whale tick sequences. The effectiveness and reliability of the proposed covert communication method is verified through simulation tests.