# Best-Suited Communication Technology for Maritime Signaling Facilities: A Literature Review
## 2 Review Methodology  
PRISMA 2020 is a set of guidelines used for systematic reviews involving mixed methods, which may include qualitative and quantitative research and can be applied to original, updated, or continuously updated systematic reviews [28; 29; 30; 31]. PRISMA 2020 guidelines can benefit various researchers as comprehensive reporting allows for assessing the appropriateness of selected methods, thus ensuring the results' relevance and reliability. Comprehensive reporting also facilitates the replication and updating of paper reviews and the incorporation of systematic reviews into brief reviews and guidelines. As a result, scientific researchers can utilize pre-selected data, avoiding irrelevant information for their research topics [32; 33; 34; 35]. Considering the paper's aims, we developed and implemented the proposed methodology depicted in Figure 1.  
Figure 1 shows that the presented methodology consists of five phases, which are explained in detail.  
The first phase of the research work is related to the research topic. It is composed of defining the research topic and identifying keywords. The motivation for the research topic is derived from available data on possible issues related to data transmission from maritime signaling facilities located in the sea area. The precise and judicious selection of keywords when exploring scientific databases is emphasized to ensure an optimal and reliable search. This critical step plays a significant role in locating relevant and accurate information about scientific research. The second phase of the research involves searching and selecting literature based on the keywords identified in three of the most representative scientific databases, namely WOS (Web of Science), SCOPUS, and Google SCHOLAR. Furthermore, the basic WOS database, including all parts of the Web of Science Core Collection (SCI-EXPANDED, SSCI, AHCI, ESCI, PCI-S, CPCI-SSH, BKCI-S, etc.), was reviewed. Papers that appeared multiple times across different databases were eliminated. Additionally, the literature search was conducted on other sources such as websites, reputable maritime organizations, citation searches, etc., as per the PRISMA 2020 guidelines [29]. Exploring other mentioned sources is important to ensure a comprehensive literature search.  
According to Table 1, the criteria entered for searching in the WOS and SCOPUS databases are of identical format, while the criterion entered for the GOOGLE SCHOLAR database is different. The difference in the given criteria is due to the limitation of 256 characters in the GOOGLE SCHOLAR search. The period from 2003 to 2023 was selected to capture the most relevant and recent advancements in communication technologies applicable to maritime signaling facilities. This timeframe allows for the inclusion of established technologies (e.g., GSM, AIS), while also encompassing the emergence and development of newer technologies (e.g., LoRaWAN, NB-IoT) that have gained prominence in the last decade. Furthermore, this timeframe aligns with the increasing focus on remote monitoring and IoT solutions in the maritime sector.  
The third phase of this paper's development includes a detailed analysis of the selected literature, which includes reading and taking relevant notes, determining relationships and patterns among the papers, and identifying specific gaps that help highlight areas where further research is needed and can guide future studies.  
The proposed methodology's last two phases (Figure 1) refer to writing the actual review paper based on the data collected from the third phase, deriving the conclusions, and pointing out future research directions.  
The query format in scientific databases was divided into \"context/type of object of maritime signaling\" and \"data transmission method\". The selected keywords and the criteria for the literature search using Boolean operators (AND, OR, NOT) are presented in Table 1.  
Figure 1: Flowchart of the proposed research methodology.