## 1 Introduction  
### _1.1. The Emergence of 6G in Maritime Communications_  
Maritime Communication Networks (MCNs) play a crucial role in ensuring seamless connectivity for vessels, offshore platforms, and coastal infrastructures. Given that more than 90% of global trade is transported by sea, the ability to maintain reliable and high-speed communication is essential for operational efficiency, safety, and economic sustainability [1]. Reliable connectivity at sea enables critical functions such as real-time navigation support, ensuring vessels can operate efficiently while avoiding hazards and optimizing routes. Safety applications, including distress signaling, emergency response coordination, and weather monitoring, heavily depend on uninterrupted communication channels [2]. Furthermore, efficient logistics and supply chain management require continuous tracking of cargo, fleet coordination, and automated port operations, all of which are facilitated by advanced communication networks. Beyond operational aspects, crew welfare has become an increasing priority, with high-speed internet access providing remote healthcare, training opportunities, and connectivity with families, ultimately improving working conditions for seafarers [3]. As maritime operations become more data-driven and technology-dependent, the evolution of communication networks is essential to support the growing demands of the maritime industry. Recent developments in MCNs have introduced several networking paradigms to address the challenges of connectivity across vast oceanic environments. Dominant among these are Low Earth Orbit (LEO) satellite-based networks, which offer global coverage with reduced latency compared to traditional geostationary satellites and are increasingly seen as a backbone for maritime broadband services (e.g., Starlink Maritime, OneWeb) [4]. In parallel, air-to-sea (A2S) communication networks enabled by high-altitude platforms (HAPs), unmanned aerial vehicles (UAVs), and even airborne base stations are gaining traction for delivering high-capacity links to moving vessels within line-of-sight (LoS) ranges [5,6]. Coastal and offshore areas continue to rely on terrestrial cellular networks, including specialized 4G/5G deployments on oil rigs and port infrastructure. Additionally, ship-to-ship (S2S) and ship-to-shore (S2 Sh) mesh-based communication systems are employed for local coordination and information dissemination, particularly in dense maritime traffic zones [2]. Hence, the current MCN architecture is inherently heterogeneous, combining satellite, aerial, terrestrial, and maritime ad hoc networks (MANETs), often with custom-built solutions to meet specific regional, economic, or operational needs. However, these disparate systems often suffer from fragmented interoperability, limited adaptability, and inconsistent quality of service (QoS), especially in dynamic maritime conditions. This diversity and fragmentation highlight the need for a unified, intelligent, and scalable communication framework, precisely where 6G technologies can make a transformative impact [7]. 6G is expected to revolutionize maritime communication with higher data rates, ultra-low latency, and Artificial Intelligence/Machine Learning (AI/ML)-driven networks. Its integration of terahertz (THz) communication and intelligent reflecting surfaces (IRS) will enable seamless, high-speed, and ultra-secure connectivity [8]. AI-powered network automation will also enhance efficiency, optimizing bandwidth and reducing energy consumption. Since the maritime industry heavily relies on seamless and uninterrupted connectivity for navigation, safety, logistics, and operational efficiency, 6G becomes crucial for addressing the limitations of current networks. Unlike 5G, which depends on terrestrial infrastructure and satellite backhauls, 6G is expected to provide a fully integrated ecosystem combining terrestrial, satellite, aerial (i.e., HAPs and UAVs), and even underwater communication networks to enable global coverage, even in deep-sea regions [6].