## 1 Introduction  
With the increase in underwater activities, the development of marine resources has become particularly important. Underwater equipment such as Remote-Operated Vehicles (ROVs) and underwater robots are the main tools to explore marine resources and are widely used in the field of seismic acquisition. On the one hand, ROVs can automate nodal seafloor acquisition operations, and on the other hand, they can also retain the technical advantages of the ocean bottom node systems [1, 2]. ROVs can be integrated into the Wi-buoy architecture so that low latency operation can be conducted in cells having a low arrival rate of packets [3]. As a key technology of underwater equipment, underwater wireless communication plays an important role. To transmit significant amounts of data without error, the demand for high-speed and reliable underwater data transmission keeps increasing [4, 5]. In recent decades, many efforts have been made to find reliable and cost-effective communication methods [6, 7]. Underwater acoustic communication (UAC) technology is the most mature and widely applied underwater communication technology, which has the advantages of long communication distance and high reliability. At the same time, due to the slow propagation speed and narrow bandwidth of acoustic signals, acoustic communication technologies have the problems of low transmission rate and high transmission delay in long-distance communication [8; 9]. Underwater visible light communication (UWVLC), which has the advantages of small system size and low energy consumption, can achieve a much higher transmission rate than UAC. However, due to the absorption, attenuation, and line-of-sight propagation characteristics of light, UWVLC systems usually require optical alignment to establish a reliable communication link [10; 11]. In recent years, more and more attention has been paid to the communication methods of underwater equipment. A new modular underwater robot has been proposed in paper [12], which integrated a visible light communication (VLC) module into an underwater unmanned vehicle based on the UAC remote control. At the same time, the VLC modem transmits data at a rate of 320 kb/s. By loading an optical communication terminal on the submersible of their research institute, [PERSON] et al. realized real-time video transmission over a distance of 100 m at a bit rate of 1 Mbps [13]. [PERSON] et al. have conducted many experiments to transmit 100 MB high-capacity data files between submarine nodes and autonomous underwater vehicles (AUV) at a bit rate of no more than 10 Mbps through a VLC modem. In their experiment, they transferred more than 5 GB files in 4.5 h and maintained the optical communication link in a cylindrical reliable communication range with a radius of 25-75 m and a depth of 125 m [14; 15]. Their experimental results demonstrate the feasibility and superior performance of VLC in underwater mobile wireless communication applications. In addition, long-term research also has been carried out on hybrid communication methods in underwater equipment. [PERSON] et al. proposed optical communication for high-speed data communication over short distances, while UAC was used for long-distance control signal transmission and optical communication auxiliary alignment [16]. The simulation results showed that their hybrid communication scheme had higher throughput and energy efficiency. In 2019, they pointed out that when the optical communication link was stable, the video signal was directly transmitted; while, when the optical communication link was interrupted, the video signal was extracted into compressed static image frames by algorithms such as Sobel edge detection and Gaussian blurring and transmitted through underwater acoustic communication [17]. An underwater hybrid acoustic-optic communication scheme was proposed in [18].