## 2 A2S Integrated MIoT
### Key Technologies of the MIoT  
Due to the heterogeneity of maritime communication network segments, in order to better monitor, collect, and disseminate relevant information, different sensor technologies (STs) and communication technologies (CTs) are often used to adapt to different environments and propagation characteristics [43]. IoT technology integrates the sensor technology, communication technology, embedded technology, and other technologies. The IoT also has its own unique methods in relevant data processing and storage. We will focus on the relevant functions of some key technologies for the MIoT, and analyze the security challenges that exist in order to solve the processing [44]. 1. Sensor technology (ST) The MIoT is a system based on ST which is used for monitoring and collecting marine environmental data. Sensors are installed in various locations and devices in the ocean to sense different parameters and conditions [45]. These parameters can include ocean temperature, salinity, pressure, water quality, light, and more [46]. At the same time, ocean sensors have a variety of types and functions for monitoring and  
Figure 1: Survey structure. collecting marine environmental data. Here are some common ocean sensor types and their features:  
* Temperature sensor: Used to measure the temperature distribution of the ocean [47]. Common STs include resistive temperature sensors and thermal conductivity sensors. * Salinity sensor: Measures the salinity distribution of the ocean. A conductivity sensor is one of the commonly used salinity STs [48]. * Pressure sensor: Used to measure the depth and pressure distribution of water in the ocean. Pressure sensors are widely used in marine scientific research and marine engineering. * Light sensor: Measures light intensity and spectral distribution in the ocean. This is important for understanding phytoplankton distribution, photosynthesis, and ecosystem function [49]. * Water quality sensor: Used to monitor dissolved oxygen, chemical concentration, nutrients, toxic substances, etc., in water. They help to assess the state of marine water quality and environmental health [50]. * Sonar sensor: Uses sound waves to measure and detect marine life, seafloor terrain, and obstacles. These sensors are commonly used in marine ecological research and ocean navigation [51]. * Oxygen sensors: Used to measure the amount of dissolved oxygen in the ocean, which is essential for biological survival and biogeochemical processes [52]. * Video and image sensors (VAISs): Video and images in the ocean are recorded using camera equipment for monitoring marine life, the marine substrate, and human activities [53]. Overall, MIoT ST can help us to better understand and monitor the marine environment, providing important support for marine scientific research, resource management, and marine environmental protection. 2. Communication technology (CT) With the increasing frequency of maritime activities, the development of maritime CT has an important strategic position [54]. However, due to the complex and variable marine environment, inconsistent standards of communication systems, and other factors, the development of marine communication lags behind land-based communication systems. Therefore, in order to adapt the marine communication to different environments and communication characteristics, different CTs are usually adopted. At the same time, the CT of the MIoT plays a crucial role in transmitting sensor data and realizing the functions of the MIoT. Below, we introduce the communication protocols and technologies used for the MIoT. * Cellular network: A cellular network is a wireless CT that enables communication with the internet by connecting MIoT devices to BSs on land. This communication can use different communication protocols such as 2G, 3G, 4G, and 5G. Cellular networks feature wide coverage and high-speed data transmission for a wide range of MIoT applications [55]. * SC: SC is a CT widely used in maritime dense communication environments.