1  
Center of Networked Computing, Temple University, Philadelphia, PA 19122, USA; [EMAIL_ADDRESS]  
2  
Department of Cyber Science, United States Naval Academy, Annapolis, MD 21402, USA; [EMAIL_ADDRESS]  
Correspondence: [EMAIL_ADDRESS] (N.N. ); [PERSON]DDRESS] (A.S.)  
T.S. Internet of Ships (IoS) and maritime IoT are becoming increasingly popular [2], and their numerous applications are presented in Figure 1. A more crucial aspect of the maritime industry and scientific research is the ability to connect devices in order to facilitate navigation and data collection. The maritime environment differs significantly from conventional land propagation environments since there are no physical barriers such as buildings or hills to obstruct the wireless signals. However, when considering wireless communications over inland waterways, it is important to account for potential obstacles such as buildings, bridges, and vessels passing beneath. These obstructions primarily impact large vehicles and buildings located near the waterways. It is also important to consider equipment located in offshore areas and vessels located in deep-sea regions when considering wireless communications over the sea. Furthermore, compared to terrestrial wireless communications, maritime wireless communications must take into account the combined air-water-land effects [1]. Furthermore, cities and areas bordering waterways and maritime traffic areas should expect customer demand in those regions as well as in their traditional terrestrial base. This demand will bring additional infrastructure requirements to include wireless coverage, network traffic, and power for supporting ancillary systems. The diverse set of platforms of maritime communications widely acknowledged and accepted in the current literature [3, 4, 5], shown in Figure 2, are as follows:  
1. Land platforms consist of satellite stations, cellular towers, and UAV stations, among other things. 2. Water platforms can be categorized into three layers--seabed, underwater, surface. The seabed layer consists of various sensors; the underwater layer consists of AUVs and submarines, among other things; and the surface layer consists of ships, buoys, and USVs, among other things. 3. Air platforms consist of UAVs and Hawkeye aircraft that play a critical role in relaying air-to-air and ship-to-air radio communications. 4. Space platforms consist of two types of satellites--navigation satellites and communication satellites--in three possible orbits--low earth orbit (LEO), medium earth orbit (MEO), and geostationary orbit (GEO). Software-defined radio (SDR) and software-defined network (SDN) are both examples of software-defined technologies that are revolutionizing traditional hardware-based networks and communications systems. SDR uses software to replace hardware in radio systems, while SDN uses software to abstract and automate the network control functions. Both SDR and SDN provide greater flexibility and programmability, enabling the development and deployment of more agile and adaptive systems. More importantly,  
Figure 1: Key emerging applications of IoS [2]. SDR and SDN can be integrated to create dynamic, software-defined radio access networks (SD-RANs), which can improve the overall network performance, reliability, and security [6]. In the context of maritime communication, SDR and SDN can offer significant advantages over traditional hardware-based networks and communications systems. SDR can be used to create more flexible and adaptive radio systems, which are particularly useful in dynamic maritime environments [7]. In addition, SDR can be used to dynamically adjust radio frequency and modulation parameters to improve communication quality and reliability, even in very challenging environments. Similarly, SDN can be used to create more efficient and automated network management systems for maritime communication networks [8]. For example, SDN can be used to centralize network control and automate network configuration and monitoring functions.