Mobile Relaying Between USV and AUV Under FER Constraints for Underwater Data Transmission

The use of underwater unmanned vehicles has proven to be an efficient method for reliable marine data collection. For this purpose, we utilize an unmanned surface vehicle (USV) as a mobile sink and an autonomous underwater vehicle (AUV) as a mobile relay to reduce communication errors. As communication reliability depends on receiving and relay positions, our study focuses on the placement of mobile vehicles to ensure reliable collaborative communication. For shallow-water sensors, we formulate receiving positions that can meet a specific frame error rate (FER) requirement as the FER-restricted area (FRA), where USV can collect data directly. For deep-water sensors, we use the collaborative relay of USV and AUV to collect data. As mobile receiving and relaying offer more possibilities than fixed, we define all possible receiving and relay positions as the possible FER-restricted area (PFRA) for both USV and AUV, and approximate them with two geometry formulas. Within PFRA, reliable cooperative relaying can be achieved. Simulation results verify that the approximate FRA and PFRA are consistent with real values.