Symmetric Connectivity of Underwater Acoustic Sensor Networks Based on Multi-Modal Directional Transducer

Lin

2023

Sensors

Spectrum-sensing technology is crucial for the development of underwater acoustic communication networks and plays a key role in detecting spectrum holes and channel occupancy. Energy detection technology, as the fundamental spectrum sensing technology in cognitive radio, has reached a mature level of development. Its application in hydroacoustic communications can significantly enhance the utilization of the hydroacoustic spectrum. However, due to the complexity of the hydroacoustic channel compared with that of the radio channel, the traditional double-threshold energy detection technique faces challenges such as fixed threshold values and limited flexibility. To address this, we propose a model for the hydroacoustic channel that incorporates a weight factor based on the signal-to-noise ratio in the algorithm. This allows for adaptive threshold values based on the user’s signal-to-noise environment, reducing false detection rates and improving overall detection performance. Through simulation experiments and comparisons, our proposed signal-to-noise weighted collaborative spectrum-sensing technique demonstrates superior detection performance compared with other spectrum-sensing techniques.

Section: Introductionmentioning

confidence: 99%

Spectrum-Weighted Fusion Cooperative Detection Algorithm Based on Double Thresholds for Underwater Acoustic Networks

Lin

2023

Sensors

“…Therefore, reliable wireless network communication is the focus of NAN in a smart grid. One of the feasible methods to achieve reliable wireless communication is fault-tolerant topology control [16,17]. The fault tolerance and invulnerability of wireless NAN can be improved by appropriate topology design in the case of partial node failure [18].…”

Section: Introductionmentioning

confidence: 99%

A Hierarchical Network with Fault Tolerance by a Multi-Factor Method for Neighborhood Area Network in Smart Grid

2022

Sensors

The neighborhood area network of a smart grid usually has hierarchical wireless communication. Due to forwarding and processing more data, the upper-layer nodes are more likely to suffer congestion and energy exhaustion. This phenomenon leads to the failure of uploading data to the control center. To solve this problem, this paper proposes a scheme for constructing a multi-factor fault-tolerant hierarchical network. This scheme firstly defines a criterion for the generation of redundant links by multi-factor method in a hierarchical wireless network with the characteristics of the neighborhood area network. Then the redundant links are used to reconstruct the existing topology of the neighborhood area network for improving fault tolerance. Finally, a greedy routing algorithm is put forward to select a proper data transmission path by bypassing low energy nodes, further reducing the failure of uploading data to the control center. The simulation results show that the proposed scheme can effectively improve the fault tolerance of the network topology of the wireless neighborhood area network and balance the network energy consumption. Compared with the original scheme, the proposed scheme improves the fault tolerance by 35% and the relative transmission rate by 21%.

Underwater Directional Acoustic Source Based on Pentamode Material

Zhao,

Wang,

Wang

et al. 2023

Acta Mech. Solida Sin.

An underwater directional acoustic emitter is conceived with a highly anisotropic lattice material, whose acoustic characteristics manifest strong dependence on the orientation of the lattice material’s principal axis. Exploiting these features, a cylindrical structure made of such anisotropic lattice material is engineered to possess distinct impedance values in different directions, thereby facilitating wave emission along the principal axis while inducing reflection in other directions. Notably, through numerical simulations, it is demonstrated that the emission direction can be effectively manipulated by adjusting the principal axis orientation, concurrently enhancing the emitted power. In contrast to previous directional acoustic structures, the compact emitter presented in this study can get rid of the size-wavelength constraint, enabling effective control of low-frequency waves.