A Multiobjective Optimization Algorithm-Based Directional Reception TDMA Protocol for Underwater Acoustic Networks

This study introduces MOVTDMA, a novel directional reception time-division multiple access (TDMA) protocol optimized for underwater acoustic sensor network (UASN) using a multiobjective optimization algorithm. To address the high-data-rate communication requirements of underwater acoustic networks, MOVTDMA utilizes the directional reception capabilities of vector hydrophones (VHPs) to enhance network throughput and robustness through spatial reuse technology. By scheduling transmission slots and VHPs' steering angles, the protocol enables parallel data transmission across multiple links, effectively maximizing network performance. The proposed protocol models the scheduling problem as a multiobjective optimization problem and efficiently solves it using the nondominated sorting genetic algorithm II (NSGA-II) algorithm. Utilizing a novel labeled tree-based starting slot encoding scheme, steering angle prior information, and a hash-based memory search mechanism, MOVTDMA optimizes convergence speed and prevents redundant calculations. Simulation results demonstrate significant improvements in network throughput and robustness compared to existing TDMA-based media access control (MAC) protocols in UASNs, highlighting MOVTDMA's potential in high-data-rate underwater applications. This approach offers a promising solution to the challenges of underwater acoustic communications, balancing network throughput with robustness and effectively managing spatial reuse in dense acoustic environments.