###### Abstract  
The growing demand for communication technology capable of providing high transmission rates in maritime environments has led to the exploration of the very high frequency (VHF) data exchange system (VDES) as a promising solution. The VDES, the integration of an automatic identification system (AIS), application-specific messaging (ASM), and VHF data exchange (VDE), offers improved transmission rates and stable connections compared with existing technologies. Although the VDES supports high transmission rates through various modulation and coding scheme (MCS) technologies, it lacks a standardized mechanism for controlling MCS parameters and relies on user algorithms for operation. In this paper, we introduce the maritime auto-rate fall-back (mARF) technology, designed to effectively address the challenges of maritime communication scenarios using the MCS framework provided by the VDES. mARF technology incorporates fast drop-out and recovery mechanisms to swiftly adapt to changing MCS types in the presence of deep nulls, a common occurrence in maritime communication environments. These adaptive thresholds for fast drop-out and recovery operations are dynamically learned using historical communication data. Through extensive simulations, we demonstrate the effectiveness of mARF in enhancing the MCS control capabilities of the VDES. Our results show a significant performance improvement of 18% compared to the existing model, validating the potential of mARF in optimizing maritime communication channels and supporting a high transmission rate. link adaptation; VDES; maritime communication; auto-rate fall-back; modulation and coding 20241322024132  
To overcome these limitations, various efforts have been made to leverage existing cellular mobile communication or Wi-Fi technologies for maritime communication. For example, [PERSON] et al. proposed maritime communication using LTE to provide coastal users with wide coverage and high data transmission rates [5]. [PERSON] applied 5G technology to maritime communication to support higher data rates [6]. By contrast, [PERSON] et al. proposed maritime communication that achieved a communication range of 7 km at 1 Mbps using 802.11n-based Wi-Fi technology [7]. [PERSON] et al. utilized the TV white space (TVWS) spectrum at 700 MHz to propose cost-effective and wide-bandwidth communication between ships and coastal infrastructure, while [PERSON] et al. suggested long-range communication technology of up to 100 km using the TV spectrum [8; 9]. However, these efforts have primarily applied existing cellular and WLAN technologies to the maritime communication environment and still have limitations regarding their widespread adoption in real maritime communication scenarios. The VHF data exchange system (VDES) is a standard technology developed for next-generation maritime communication [10]. Through an amendment to the Safety of Life at Sea (SOLAS) convention, the International Maritime Organization (IMO) has mandated the incorporation of VDES technology for all passenger vessels, vessels over 300 tons engaged in international voyages, and vessels over 500 tons not engaged in international voyages. The VDES integrates an AIS, application-specific messaging (ASM), VHF data exchange--terrestrial (VDE-TER), and VHF data exchange--satellite (VDE-SAT), offering support for various applications compared to existing maritime communication technologies. It also supports link adaptation (LA) to achieve high-throughput link speeds, and the physical layer supported for link adaptation in the VDES has been presented in several studies [11; 12]. However, while the VDES defines multiple modulation and coding scheme (MCS) technologies for LA operation, it does not provide definitions for algorithms on how to utilize these MCS technologies for LA operation. Additionally, there have been attempts to optimize link adaptation in the mmWave and Ka bands by expanding the frequency range. Representatively, [PERSON], [PERSON] et al. and [PERSON], [PERSON] et al.