I. Introduction
The oceans occupy nearly 71% of the Earth’s surface and provide abundant resources for human survival [1], [2]. In ocean exploration, marine emergency events occur frequently, such as tsunamis, shipwrecks and oil spills. The occurrence of maritime accidents not only causes great losses to human beings but also destroys the marine ecosystem. Due to the complexity of the marine environment, it is common to establish surface base stations to realize underwater communications. However, when carrying out maritime emergency response missions, the sea surface base station is unable to achieve fair coverage, which in turn leads to high latency or failed transmission of underwater sensed data.