An OFDMA Downlink Acoustic Communication Scheme for AUV-Based Mobile Underwater Sensor Network

Due to complex underwater acoustic (UWA) channels, mobility characteristics, and constrained energy of autonomous underwater vehicles (AUVs), a communication scheme that can ensure real-time and reliable communication with less energy consumption of the AUV-based mobile underwater sensor network is necessary. In this study, orthogonal frequency-division multiplexing access (OFDMA) technology, with high spectral efficiency and strong anti-multipath capability, is applied, and a multi-AUV communication scheme based on OFDMA downlink communication is proposed. To ensure real-time communication and avoid access conflicts, an OFDMA access time control scheme based on AUV motion sensing is proposed, together with a low-complexity subcarrier allocation algorithm for UWA OFDMA downlink communication to reduce the average bit error rate (BER) and ensure the reliability of the communication. Results of simulations and sea experiment show that the BER performance of the proposed subcarrier allocation algorithm is better than that of the existing algorithms.