Effects of Water Surface Waves on a Sound-Millimeter Wave-Based Cross-Medium Wireless Communication System

Wireless cross-medium communication between underwater sensors and the outside world is a critical problem for marine exploitation. The sound-millimeter wave (mmWave)-based cross-medium communication system is a potential technology to solve the problem. However, the system is dramatically affected by random waves on the water surface. Here, the effects of waves on cross-medium wireless communication are analyzed. A system that combines a multichannel mmWave radar sensor and an underwater acoustic transmitter was applied to conduct a field experiment. Detailed signal processing methods and results are presented based on the system, which confirms the above analysis and shows the possible utilization of the multichannel mmWave radar sensor to solve the cross-medium wireless communication problem. A phase-difference-based space diversity technique is proposed to improve the communication performance on wavy water surfaces. The comparison results demonstrate the effectiveness of this technology.