## 1 Introduction  
### Background  
Currently, marine equipment and vessels are often isolated, they cannot effectively exchange information, hence they cannot work together effectively. The construction of the maritime internet of things (MIoT) enables real-time connectivity and information sharing among various devices, thereby enhancing the efficiency and security of marine equipment [1]. The MIoT refers to a network system that connects ships, marine equipment, and sensors, etc., and utilizes modern communication and information technologies to realize the interconnection between marine equipment and other equipment [2]. By collecting, transmitting, processing, and applying data, the MIoT provides the real-time monitoring, remote control, and intelligent decision support to achieve comprehensive awareness, intelligent management, and collaborative work of maritime objects. The MIoT stems from the development of modern science and technology and the need for in-depth development and utilization of marine resources [3, 4]. With the vigorous development of artificial intelligence, big data, the internet of things (IoT), and other technologies, the MIoT has become an important force driving the development of the marine economy [5].  
[PERSON] et al. [6] showed that the MIoT is a special kind of IoT system and is very different from the IoT on land in terms of connection methods, device types, data transmission, and so on. The complexity and variability in the marine environment make the construction and application of the MIoT more extensive and has far-reaching significance [7]. [PERSON] et al. [8] showed that the MIoT needs to consider the particularities of limited maritime communication, the complex maritime environment, and the operator safety. Moreover, the application field of the MIoT is expanding day by day, which has become an important supporting force for promoting the transformation and upgrading of the marine economy and building maritime power [9].  
Since air-to-sea (A2S) integrated communication is crucial in the MIoT, we introduce A2S integrated communication technology. This technology seamlessly connects air resources such as aircraft drones and marine equipment, ships, and other ground resources [10]. [PERSON] et al. [11] relied on traditional coastal base stations (CBSs). The signal coverage was limited thus transmission efficiency was low and the flexibility was poor. But A2S integrated maritime communications have the following advantages:  
* Wide coverage: Through satellite communication (SC) technology, A2S integrated communication can achieve global coverage, even in the deep-sea area far from the land, and can also carry out communications and data transmission (DT), effectively solving the problem of limited maritime communication [12].
* Strong real-time capabilities: A2S integrated communication provides real-time DT and communication capabilities, minimizing DT delays and ensuring real-time monitoring, control, and decision support for the MIoT [13].
* High bandwidth and large capacity: A2S integrated communication provides broadband and large-capacity communication channels, meeting the needs of high-speed DT for the MIoT and supporting large-scale DT and application among marine equipment [14].
* Flexible and schedulable: A2S integrated communication possesses flexible scheduling capabilities, allowing communication resources to be allocated to different areas or tasks as needed, ensuring the communication quality and reliability of each node of the MIoT [15].  
In summary, the introduction of A2S integrated communication in the MIoT greatly expands the communication coverage, improves the communication quality and data transmission capacity, and provides strong support for the construction and application of the MIoT.