Best-Suited Communication Technology for Maritime Signaling Facilities: A Literature Review

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This paper provides a valuable framework for selecting the most optimal communication technology for establishing the remote monitoring of maritime signaling facilities, contributing to enhanced navigation safety, and developing sustainable and efficient technical systems in the naval sector.

Abstract

The remote monitoring of maritime signaling facilities is one of the marine navigation safety rules essential for ensuring global maritime traffic. Some maritime signaling facilities have not yet implemented remote monitoring systems. This challenge is posed by factors such as insufficient signal range, limited availability of electrical energy, or various economic reasons. Therefore, this paper reviews the current and relevant scientific literature on 10 communication technologies for maritime signaling facilities in the last two decades using PRISMA guidelines. PRISMA 2020 represents guidelines for conducting systematic review papers using mixed methods, including their applicability to various reviews. In addition, this paper analyzes the selection of the best-suited communication technology for communication between maritime signaling facilities. The results show that, initially, 214 papers met the specified criteria, and after applying the filtering, it was narrowed to 29 relevant papers for the research topic. Surprisingly, almost half of them were found in databases other than WOS, SCOPUS, and GOOGLE SCHOLAR. Also, LoRa WAN is the most energy-efficient and cost-effective option, with a consumption rate 2.14 times lower than AIS and NB-IoT. To summarize, it has been found that LoRa WAN represents the optimal communication technology for transmitting data from maritime signaling facilities across long distances.

1. Introduction

Maritime navigation safety includes a set of rules such as radio communication, construction of ships, fire protection, life-saving appliances, the carriage of cargo, and special measures for high-speed ships. Navigation under severe environments requires information gathering that can compensate for adverse conditions and a cautious mindset that can ensure safe navigation. The increased maritime traffic over the past decade has also led to a significant increase in traffic in seaports [1,2,3]. As maritime activities continue to grow worldwide, there is a corresponding need for an increased number of marine aids to navigation (AtoNs) as soon as possible. The purpose of AtoNs is to mark navigational routes and identify obstacles that pose hazards to navigation. These obstacles are assumed to be static and do not change shape [4]. Obstacles can be marked by fixed or floating objects of maritime signaling. Floating objects used for marine signaling are known as buoys. A phenomenon known as buoy drift refers to the movement or displacement of a buoy from its original position. The buoys drift often and can be caused by tides, marine currents, wind patterns, and water temperatures [5,6]. Furthermore, by changing their positions, the AtoNs lose their functionality, resulting in inaccurate information about the navigational routes for ships. This could lead to maritime accidents, ship collisions, groundings, and other negative consequences for human lives, property, and marine ecology. To mitigate these risks, accurate and reliable AtoN positions must be maintained. The traditional, manual monitoring of AtoN positions requires on-site inspections. By establishing a remote monitoring system, real-time data about the status and position of AtoN are possibly received. The combination of remote monitoring and GPS (global positioning system) technology enables proactive monitoring, reduces navigation risk, and ensures safety, reliability, cost-efficiency, and effective maintenance [7,8]. Guided by the aforementioned issues, a literature review in relevant scientific databases was conducted using keywords related to the discussed topic to select the most optimal communication technology for this purpose. The identified scientific papers were filtered according to the criteria outlined in the subsequent section of the paper. A detailed analysis of the papers and the technologies employed for data transmission, crucial for a remote monitoring system, was conducted. Moreover, this paper adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines to ensure that the review process meets adequate standards. The PRISMA guidelines allowed us to clearly define search criteria, data sources, and study selection procedures, ensuring the objectivity and reproducibility of our review.

Furthermore, the motivation for writing this paper was the state of the remote monitoring system for maritime signaling facilities in the Croatian part of the Adriatic Sea as a typical example of a rugged coastline. It is worth noticing that a Croatian part of the Adriatic Sea has become the top yachting destination in the world in the last two decades [9,10]. Furthermore, the coastline of the Adriatic region is highly rugged [10]. The Adriatic coast makes up almost a quarter of the European part of the Mediterranean Sea coast, with 1.246 islands, islets, and rocks [9,10,11,12,13]. Based on the information presented, it can be emphasized that the Adriatic Sea analysis carried out in this work also applies to other sea locations worldwide. There are 1275 marine AtoNs installed in the Croatian Adriatic. Of this total number, approximately 13% of AtoNs consist of floating objects of maritime signaling—buoys. Of the mentioned total AtoNs, 103 are under remote monitoring, representing 8,07% of the total marine signaling facilities [14]. It has to be pointed out that the construction of new AtoNs does not necessarily imply an increase in remote monitoring capabilities. The transmission of data collected through the existing remote monitoring system uses the Global System for Mobile Communications (GSM) network and data traffic. Moreover, the literature states that GSM has become one of the greatest achievements in the field of science, revolutionizing telecommunications and communications worldwide [15,16]. However, the GSM signal is not available at all micro-locations of AtoNs due to natural obstacles such as several islands, rocks, etc. [17,18]. This poses a problem in establishing and increasing the number of monitored maritime signaling facilities, which is one reason newly constructed objects are not remotely monitored. Additionally, satellite systems like Iridium offer global coverage. However, their high costs and energy demands make them less suitable for autonomous maritime systems, especially in remote areas with limited energy resources [19,20]. Other technologies, such as VDES and 5G-NR (5G- New Radio), also face challenges in maritime environments due to infrastructure requirements and limited coverage, further emphasizing the need for cost-effective and energy-efficient communication solutions tailored to these unique conditions [19,20,21,22]. One possible solution to this problem is the application of technologies such as AIS (Automatic Identification System), MaxStream, LTE (Long Term Evolution), NB-IoT (Narrowband Internet of Things), LoRa WAN (Long Range Wide Area Network), GSM (Global System for Mobile Communications), GPRS (General Packet Radio Services), 3G (Third Generation of Wireless Mobile Telecommunications Technology), VHF (Very High Frequency), or ZigBee [22,23,24,25,26,27].

Considering the significance of establishing wireless communication with all micro-locations where maritime signaling facilities are located, this systematic review paper aims to summarize, appropriately categorize, and conclude with the relevant communications technologies and their fundamental characteristics. However, the paper hypothesizes that there has been limited engagement in the remote monitoring of maritime signaling facilities. Note that the contribution of this paper, in addition to analyzing previously published papers utilizing communication technologies, selects the best-suited communication technology for establishing communication with maritime signaling facilities.

Finally, the paper is arranged in the following manner. The methodology utilized in the paper to accomplish the research results is described in Section 2. The results are trotted out and discussed in Section 3. Section 4 concludes and makes recommendations for future work.

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.

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. The query format in scientific databases.

DATABASE	SET OF ENTRY CRITERIA
WEB OF SCIENCE	TI = (((“safety of navigation”) OR (“navigation safety”) OR (“maritime signalling facilities”) OR (“buoy”)) AND ((“communication”) OR (“gsm”) OR (“l OR a”) OR (“ais”) OR (“LTE”) OR (“GPRS”) OR (“wireless”) OR (“iot”) OR (“industry 4.0”) OR (“SENS OR S”) OR (“IOT4”) OR (“fusion solution”) OR (“remote monit OR ing”)))
SCOPUS	TITLE ((“safety of navigation” OR “navigation safety” OR “maritime signalling facilities” OR “buoy”) AND (“communication” OR “gsm” OR “lora” OR “ais” OR “lte” OR “gprs” OR “wireless” OR “remote monitoring” OR “iot” OR “industry 4.0” OR “sensors” OR “iot4” OR “fusion solution”)) and pubyear > 2003 and pubyear < 2023
GOOGLE SCHOLAR	ALLINTITLE: ((“safety of navigation”) OR (“navigation safety”) OR (“maritime signalling facilities”) OR (“buoy”)) AND ((“communication”) OR (“gsm”) OR (“lora”) OR (“ais”) OR (“lte”) OR (“gprs”) OR (“wireless”) OR (“remote monitoring”))
OTHER SOURCES	KEYWORDS: “maritime signalling facilities”, “safety of navigation”, “communication”, “gsm”, “lora”, “ais”, “lte”, “gprs”, “wireless”, “remote monitoring”, “iot”, “industry 4.0”, “sensors”, “iot4”, “fusion solution”

.

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.

3. Results and Discussion

This paper relies on data from the WOS, SCOPUS, and GOOGLE SCHOLAR databases, among others. The analytical literature review was performed using the criteria in Table 1 over 21 years (from 2003 to 2023) and yielded 214 relevant scientific papers, as shown in Figure 2.

The flowchart from Figure 2 for searching and filtering papers can be divided into three stages. The first stage is “document identification”, where initial analysis is performed using a set of entry criteria for searching the WOS, SCOPUS, and GOOGLE SCHOLAR databases, among others (Table 1). In addition to the aforementioned databases, our search included the following sources: Hrcak, websites of reputable maritime organizations, and citation searching.

In the second stage, named “Document screening”, a set of exclusion rules is applied to derive a filtered number of papers for stage three (Figure 2). The last stage, “Document included”, represents the selected papers analyzed in the paper.

3.1. Analytical Literature Review

In Figure 2, a total of 43 papers that met the specified search criteria were identified during the search in the WOS scientific database. Onward, searching the SCOPUS database using Table 1, from 2003 to 2023, a total of 131 papers were found. Also, the search of the same period in the GOOGLE SCHOLAR database resulted in 21 papers that met the specific criteria from the table. Searching other databases provided 19 additional relevant scientific papers. The time scale of analyzed papers and basic statistical metrics for each database is shown in

Table 2. The search for relevant references over 21 years from 2003 to 2023 before (and after) filtering.

SCIENTIFIC DATABASES
Obs. Years	WOS	SCOPUS	GOOGLE SCHOLAR	OTHER
2003	0 (0)	0 (0)	0 (0)	0 (0)
2004	0 (0)	1 (0)	0 (0)	0 (0)
2005	1 (0)	5 (0)	2 (0)	0 (0)
2006	2 (0)	8 (2)	0 (0)	0 (0)
2007	0 (0)	5 (0)	0 (0)	0 (0)
2008	0 (0)	1 (0)	0 (0)	0 (0)
2009	0 (0)	4 (0)	0 (0)	0 (0)
2010	0 (0)	5 (0)	1 (0)	0 (0)
2011	0 (0)	2 (0)	1 (0)	1 (1)
2012	2 (0)	6 (1)	1 (1)	2 (2)
2013	1 (0)	6 (0)	0 (0)	0 (0)
2014	0 (0)	4 (0)	0 (0)	2 (1)
2015	4 (0)	5 (0)	1 (0)	1 (0)
2016	1 (1)	5 (0)	3 (1)	1 (0)
2017	2 (0)	7 (0)	0 (0)	2 (1)
2018	7 (2)	13 (0)	4 (0)	0 (0)
2019	8 (3)	22 (0)	2 (0)	2 (2)
2020	4 (0)	9 (1)	1 (0)	2 (2)
2021	6 (0)	13 (1)	4 (2)	2 (2)
2022	4 (0)	8 (0)	1 (1)	4 (2)
2023	1 (0)	2 (0)	0 (0)	0 (0)
Total	43 (6)	131 (5)	21 (5)	19 (13)
AVERAGE	2.05 (0.29)	6.24 (0.24)	1 (0.24)	0.9 (0.62)
MEDIAN	1 (0)	5 (0)	1 (0)	0 (0)
STD	2.44 (0.76)	4.89 (0.53)	1.27 (0.53)	1.11 (0.84)

.

A basic statistical analysis was performed on columns to check the data from the table. A Kolmogorov–Smirnov test was performed to check the data normality. It showed that data do not come from the normal distribution (p_WOS < 0.001, p_SCOPUS < 0.001, p_GOOGLE < 0.001, and p_OTHER < 0.001). Then, a Kruskal–Wallis ANOVA test was performed to check the data’s independence between the columns. It showed χ²(3) = 29.37, p < 0.001. Thus, it can be noted that the data do not come from the same source.

In the first stage, “document identification”, only 20% of the papers met the specified search criteria in the WOS database. During the 21 years, the median is one paper per year with a standard deviation of 2.44. The most productive year, with eight published papers, was 2019 (Table 2). Furthermore, a search of the SCOPUS database from 2003 to 2023 yielded 131 papers, or 61,21%. Contrary to the WOS database, the median was five papers per year, with a standard deviation of 4.89. Similarly, to the WOS, the year with the highest number of published papers, 22, was also 2019. The GOOGLE SCHOLAR database search resulted in 21 papers, or 9.81%, during the same period (Table 2). Similarly as WOS, the median is one published paper per year with a standard deviation of 1.27. However, 2018 was the year with the highest number of published papers. Moreover, a paper search in other databases was performed, and 19 relevant scientific papers, or 8.88%, were identified. The median is 0, with a standard deviation of 1.11 papers per year. Unlike the WOS and SCOPUS databases, the highest number of papers, four, were published in 2022.

To summarize, the processed data from Table 2 show that interest in the topic has noticeably increased in the last six years compared to the observed period. This increase is graphically represented in Figure 3.

Figure 3 shows that the number of papers on the topic has increased from 2018 until today. For instance, in 2018, 24 papers were published, which is three times less than in 2005, when a total of 8 papers were published, or eight times more than the previous year, when only 1 paper on this topic was published. Additionally, the number of papers peaked in 2019, with 34 papers published.

Furthermore, the filtering criteria applied in the “Document screening” stage were as follows: (1) Duplicates, identified through manual comparison of titles, authors, and publication sources, with preference given to versions from Web of Science or Scopus; (2) Papers unrelated to the review’s subject (e.g., meteorological measurements on buoys, buoy-related energy); (3) Papers encompassing extensive research areas (e.g., analysis of communication antenna systems, antenna system optimization, satellite communication); and (4) Papers in languages other than English or Croatian. Due to resource constraints and the research team’s language expertise, we focused on articles published in English and Croatian. While we acknowledge that relevant research may exist in other languages (e.g., Chinese, Russian, or Turkish), including these articles would have required translation.

A graphical representation of the paper search and filtering process can be found in Figure 2. As shown in Figure 2, out of the initial 214 papers, 36 duplicates were eliminated. Furthermore, 87 papers with inadequate topics and 58 papers covering overly broad research areas were excluded. Only four papers were found to have a language barrier and were not included for further analysis. This exclusion process was carried out to maintain focus and relevance and resulted in 29 papers selected for further analysis in the third stage, “Document included”.

To summarize, according to the analysis of the number of papers before and after filtering, the result yielded 214 and 29 relevant papers, as shown in Table 2.

In this section, it is important to note that, after filtration, 44.82% of the papers selected for further processing were found using the “other” search method. However, it has to be emphasized that most “other” results are found, for instance, in the IEEE Xplore database.

Table 3. Overview of the selected papers.

No.	Tech.	Ref.	Conclusion
1.	AIS	[36]	AIS can be used for telemetry, but the data are still transferred using satellite communication (Iridium). It has an extensive range but comes with high costs. The specific range is not mentioned but unquestionably sufficient given the satellite communication method.
2.		[23]	The data are transmitted using the ad hoc method through AIS.
3.		[37]	The data are transferred using AIS AtoN devices, but only between two devices, utilizing standard pre-defined AIS messages.
4.		[38]	The data are transferred using AIS AtoN devices, but only between two devices, utilizing standard pre-defined AIS messages.
5.		[39]	Several communication methods have been used, and a table with a comparative display has been presented. AIS, LTE, and NB-IoT are mentioned as the three most optimal solutions for this type of data transmission.
6.	LoRa WAN	[40]	LoRa WAN network is being used experimentally, and a range of over 8 km was achieved, depending on the terrain configuration. In urban areas, the range is 2 km. Additionally, it is highlighted that the costs are very low.
7.		[41]	LoRa WAN is being used, and it boasts a maximum range of 15 km, low power consumption, and the advantage of using LoRa devices without the need for frequency licensing.
8.		[42]	LoRa WAN is being utilized, and efforts are being made to optimize the coverage of the LoRa signal.
9.		[43]	LoRa WAN was in use, and it was noted that communication had been successfully established at a distance of 15 km. The technology features low power consumption and the advantage of using LoRa devices without frequency licensing.
10.		[44]	LoRa WAN is being used, and the achieved range is 8.33 km in the worst-case scenario.
11.		[45]	LoRa WAN is being used, and a range of 15 km was achieved.
12.		[46]	LoRa WAN was used, and a range of 8.33 km was achieved.
13.		[47]	LoRa WAN is being used, and the achieved range is 110 km in open areas and 20 km in urban environments.
14.		[48]	LoRa WAN is being used, and a range of 2 km in urban areas was achieved.
15.	LTE	[49]	The LTE technology is being used, and a data transmission range of 100 km was achieved.
16.	GPRS	[50]	GPRS technology is used and highlighted for its low cost, high data transmission speed, stability, and widespread availability. It is also mentioned that the range is not limited, unlike some traditional communication methods. Furthermore, the maintenance costs are relatively low.
17.		[51]	GPRS is used with low costs, high data transmission speed, and an “always-on” option. However, the specific range is not mentioned.
18.		[52]	GPRS is used for bidirectional communication, but the specific range is not mentioned.
19.		[53]	GPRS is being used, and hardware has been developed for the project. However, the specific range or distance the GPRS communication covers is not mentioned.
20.		[54]	GPRS is being used, and LoRa and GPRS are mentioned as the alternative and sustainable methods for data transmission. The achieved range is 35 km, depending on the operator’s base stations’ configuration at each location.
21.	NB-IoT	[55]	NB-IoT is used in combination with ZigBee. If NB-IoT is unavailable, the devices can connect and transfer data using the ZigBee network, effectively using ZigBee as a backup or alternative to NB-IoT.
22.		[56]	Two technologies are being used, namely LoRa WAN and NB-IoT, and a comparison has been conducted. LoRa WAN has advantages in terms of battery life and cost, while NB-IoT excels in latency, availability, and range. The maximum range of LoRa WAN is 15 km, while NB-IoT has a range of 35 km.
23.	3G/VHF	[57]	Hybrid technology using 3G/VHF is utilized at very low costs and in a satisfactory range. The specific range is not explicitly mentioned.
24.	MaxStream	[24]	The MaxStream radio modem is being used at a frequency of 900 MHz for a pilot project, and a range of 1 km was achieved.
25.	GSM	[58]	GSM (SMS) technology is used for communication, emphasizing low costs and highlighting data security through this method. Additionally, the possibility of using GPRS for faster data transmission is mentioned. However, a specific range is not provided.
26.		[59]	The topic is generally related to data transmission. Alongside GSM, other communication technologies are mentioned, which could lead to the conclusion that the scope of the paper is too broad. However, the paper is still being analyzed.
27.		[60]	GSM is used as a reliable method; the significance of the range is not emphasized, nor has it been measured.
28.		[61]	GSM is used as a reliable method; the significance of the range is not emphasized, nor has it been measured.
29.	ZigBee	[62]	ZigBee is being used, and a range of 430 m was achieved.

presents an overview of the selected papers, each designated by a unique reference number in the paper’s references, along with the first author’s name. The table provides the publication year, the communication technology employed in the paper, and a summary of the conclusions derived from each respective paper.

3.2. State of Communication Technologies

Through the analysis of all 29 scientific papers, it was determined that a total of 10 communication technologies were used for data transmission from remote locations. These technologies include AIS (technology that enables the automatic identification and tracking of ships in real-time via VHF radio waves), LoRa WAN (wireless communication technology that allows the long-range, low-power connectivity of devices in IoT networks), GPRS (2.5G mobile technology that enables data transmission over mobile networks), NB-IoT (mobile technology for the Internet of Things (IoT) that utilizes mobile networks with long-range, low-power consumption, and supports a large number of devices in urban areas), GSM (globally adopted standard for mobile telephony, enabling voice services, SMS messaging, and low-speed data transfer), LTE (4G mobile technology that provides high-speed data transfer, improving Internet speed, voice, and video services in mobile networks), 3G (third generation of mobile networks that offers faster data transfer rates than 2G, enabling better internet access, video calls, and data transfer on the go), VHF (radio frequency range (30–300 MHz) used for medium and long-range communication, commonly employed in maritime and aviation communications), MaxStream (wireless technology based on XBee modules that enables short-range data transmission and low power consumption), and ZigBee (wireless communication technology designed for IoT applications, with low-power consumption and the ability to connect a large number of devices in a network with low data transmission speeds). Listed technologies were employed in a total of 36 practical examples that were examined in the analyzed papers. A discrepancy was observed during the analysis between the total number of analyzed papers and the number of uses for each mentioned communication technology. This discrepancy occurred because, for example, Wang et al. [1], Sinha et al. [63], and Cho and Yu [41] utilized multiple different communication technologies for data transmission in the same example, increasing the total number of uses for certain communication technologies. Consequently, this led to the increased frequency of the individual usage of certain communication technologies. The prevalence of each communication technology in the relevant scientific papers is presented in Figure 4.

The figure shows that LoRa WAN is the predominant communication technology (30.30%) for transmitting data from remote maritime signaling facilities, as determined by analyzing selected papers. AIS and GPRS were found to be represented in a total of five papers each. The least represented technologies are 3G, VHF, MaxStream, and ZigBee, each analyzed in one paper.

One of the key challenges in implementing the remote monitoring of maritime signaling facilities (AtoN) is the limited availability of reliable and energy-efficient communication technologies. Although satellite systems, such as the Iridium system, offer global coverage, their application is often limited by high costs and significant energy demands. Hensley and Heitsenrether [20] highlight that Iridium satellite telemetry enables real-time data transmission but comes with high operational costs and substantial energy consumption. These limitations make satellite technologies less suitable for autonomous maritime signaling systems, especially in remote areas where energy resources are limited [64]. Wang et al. [19] also emphasize that, while satellite-based solutions are technically feasible for maritime IoT applications, their high costs and energy requirements remain a significant barrier to widespread adoption, particularly for autonomous and energy-constrained systems.

In addition to satellite systems, other technologies such as VDES (VHF Data Exchange System) and 5G-NR are also relevant but face similar limitations in the maritime context. VDES, although promising, is still under development, and widespread implementation has not yet been achieved [65,66,67]. One of the key challenges of VDES is its limited bandwidth, which restricts the amount of data that can be transmitted efficiently over long distances, making it less effective for high-throughput applications such as real-time video streaming or large-scale data exchange [65]. Additionally, VDES operates in the VHF spectrum, which is susceptible to interference and signal degradation, particularly under adverse weather conditions or in congested maritime regions where multiple communication systems coexist [68].

Similarly, while 5G-NR technology offers high data transmission speeds and low latency, it requires dense network infrastructure, making it challenging to deploy in remote maritime regions with sparse base station coverage. Due to the high-frequency spectrum used in 5G-NR, signals attenuate quickly over long distances, necessitating a large number of small cells and repeaters, which is not feasible in sea environments [69]. Furthermore, 5G-NR’s energy consumption is significantly higher compared to other maritime communication technologies, raising concerns about sustainability and operational costs in maritime applications [70]. Additionally, the lack of standardized maritime-specific 5G-NR solutions further complicates its adoption, as existing networks are primarily designed for urban and terrestrial use cases rather than for the open seas’ vast and dynamic nature [70].

These factors collectively highlight the need for more cost-effective and energy-efficient communication solutions tailored to the unique challenges of maritime environments. While hybrid approaches that integrate satellite communication with terrestrial networks and advanced maritime mesh networks are being explored, the practical deployment of these solutions remains challenging due to regulatory, technical, and economic constraints [71].

Considering the technical issues related to establishing data transmission from maritime signaling facilities, this paper emphasizes three technical criteria for establishing communication with these objects. These criteria—signal range, power consumption, and economic aspects (cost)—were selected due to their direct impact on the feasibility and long-term sustainability of remote monitoring systems in maritime environments. Signal range is crucial because maritime signaling facilities are often located in remote and isolated areas where conventional communication infrastructure is unavailable. Reliable long-distance communication is necessary to ensure continuous data transmission and effective monitoring [72]. Power consumption is another key factor, as many of these facilities rely on limited energy sources, such as solar panels. High-energy consumption would require frequent maintenance and additional infrastructure, making low-power solutions preferable for ensuring operational efficiency and system reliability [73]. Finally, cost plays a significant role in determining the scalability and practical implementation of communication technologies. While satellite-based systems provide global coverage, their high costs often make them impractical for large-scale deployment. More cost-effective solutions enable broader adoption and reduce the financial burden associated with maintaining maritime signaling networks [74].

The key technical criteria for establishing communication with maritime signaling facilities are illustrated in Figure 5.

By analyzing the three technical criteria mentioned, a holistic understanding of communication technologies can be achieved. This analysis allows for a thorough evaluation of the technologies and their suitability for specific applications.

3.3. Range of Communication Technologies

The range of communication technologies used for transmitting signals from maritime signaling facilities is an important technical parameter, especially considering that these facilities are often located in remote marine locations. This means that maritime signaling facilities are frequently far from the coastline and, consequently, from terrestrial transmitter base stations. Moreover, due to the geographical configuration and navigational requirements for marking hazardous maritime locations, maritime signaling facilities are also distant. The range of communication technologies, i.e., the strength of the transmitted signal, is proportional to the level of the received signal or its field [15,30]. The concept of range can also be associated with coverage and connectivity [63,64,65,66,67,68,69,70,71,72,73,74,75]. All these factors pose challenges in establishing communication with such objects, and Table 3 presents the analysis of the range for each communication technology with corresponding paper references. Papers in which a particular communication technology was used, but the achieved range was not specified (n/a), have also been recorded.

Table 4. Results of the paper analysis in the context.

AIS		LoRa WAN
Range (km)	Ref.	Range (km)	Ref.
n/a	[36]	8	[40]
n/a	[23]	15	[56]
n/a	[37]	15	[41]
n/a	[38]	n/a	[42]
80	[39]	15	[41]
n/a	[23]	8.3	[44]
-	-	15	[45]
-	-	8.3	[46]
-	-	110	[47]
-	-	16	[39]
-	-	2	[30]
LTE		3G
Range (km)	Ref.	Range (km)	Ref.
100	[49]	n/a	[57]
100	[39]	-	-
GPRS		NB-IoT
Range (km)	Ref.	Range (km)	Ref.
n/a	[57]	35	[56]
n/a	[51]	n/a	[51]
n/a	[52]	100	[39]
n/a	[53]	-	-
35	[54]	-	-
VHF		MaxStream
Range (km)	Ref.	Range (km)	Ref.
n/a	[57]	1	[24]
120	[39]	-	-
GSM		ZigBee
Range (km)	Ref.	Range (km)	Ref.
n/a	[58]	0.43	[62]
n/a	[59]	-	-
n/a	[60]	-	-
n/a	[61]	-	-

shows that the highest achieved range is 120 km using VHF communication technology, as described by Cho et al., 2022 [39]. The smallest range was achieved using ZigBee communication technology (0.43 km), as defined by Hidayat et al., 2016 [62]. The ranges achieved for 3G and GSM communication technologies were not definitively specified in the analyzed papers, representing an important limitation in the literature. It is crucial to emphasize that, out of the 36 analyzed papers, sixteen papers (44.44% of the total) did not provide information about the range of communication technologies used. This lack of range data poses a significant drawback to the analysis, as access to this information would contribute to more comprehensive and accurate final analysis results. Based on the analysis conducted in the context of the achieved range, it can be concluded that the lack of a standardized approach is a common shortcoming of the available papers. Standardization is important in ensuring consistency and comparability across different studies or experiments. By utilizing a standardized approach for setting up the network and transmitting signals uniformly, the reliability of the results can be enhanced.

3.4. Electrical Power Consumption

With the rapid advancement of information and communication technologies, the consumption of electrical energy is increasing at an incredible pace, as described by Laurent, 2009 [76], and Feng et al., 2013 [77]. During the design of communication networks, performance factors like range and data transfer are important considerations. These factors ensure efficient communication. However, as electrical energy consumption has become an essential technical parameter to consider, there is growing interest in developing strategies for energy-efficient networks. Minimizing energy consumption helps reduce environmental impact and contributes to cost savings. The scientific literature contains papers that address the optimization of power consumption and compromises related to energy efficiency [77,78,79,80]. All of these considerations apply to power consumption during the establishment of communication with maritime signaling facilities, where an additional challenge is the limited availability of electrical energy.

Furthermore, power consumption analysis was performed for each of the 10 communication technologies. The results were categorized as either “low power consumption” (L) or “high power consumption” (H) based on the respective communication technology. The papers where data on power consumption level were not recorded (n/a) were also considered during the analysis. Table 4 represents the power consumption analysis results and the corresponding paper references.

From

Table 5. The results of the paper analysis concerning the electrical power consumption.

AIS		LoRa WAN
El. Power Consumption (H/L)	Ref.	El. Power Consumption (H/L)	Ref.
n/a	[36]	L	[40]
n/a	[26]	L	[56]
n/a	[37]	L	[41]
n/a	[38]	n/a	[42]
-	-	L	[43]
-	-	L	[44]
-	-	L	[45]
-	-	L	[44]
-	-	L	[47]
-	-	L	[39]
-	-	L	[48]
LTE		3G
El. power consumption (H/L)	Ref.	El. power consumption (H/L)	Ref.
H	[49]	L	[57]
GPRS		NB-IoT
El. power consumption (H/L)	Ref.	El. power consumption (H/L)	Ref.
n/a	[50]	L	[56]
L	[51]	L	[55]
L	[52]	L	[39]
L	[53]	-	-
n/a	[54]	-	-
VHF		MaxStream
El. power consumption (H/L)	Ref.	El. power consumption (H/L)	Ref.
L	[57]	L	[24]
GSM		ZigBee
El. power consumption (H/L)	Ref.	El. power consumption (H/L)	Ref.
H	[58]	L	[62]
n/a	[59]	L	[55]
n/a	[60]	-	-
n/a	[61]	-	-

, it can be inferred that the highest power consumption was recorded when transmitting data using GSM and LTE communication technologies. The lowest power consumption was observed when using LoRa WAN communication technology. The analyzed papers did not explicitly state the power consumption for AIS communication technology. Additionally, the lack of power consumption data in a significant percentage of analyzed papers (30.30%) does pose a limitation in the research. Access to this data would enhance the accuracy and completeness of the final analysis results.

3.5. Economic Aspect of Using Communication Technologies

Consistent investments in research and development aimed at improving the efficiency of communication technology result in a wealth of theoretical knowledge and various engineering solutions [32,81]. Luong et al., 2016 [82], emphasized that the economic perspective on communication technology development has gained significant attention due to its role and can be categorized into three groups for practicality: cost determination based on economic concepts, theoretical concepts, and cost determination through optimization. Determining costs based on economic concepts involves setting costs according to supply and demand, cost–benefit analysis, and market structures. Theoretical concepts apply economic theories like game theory, utility theory, and elasticity of demand to analyze pricing strategies and consumer behavior. Cost determination through optimization utilizes mathematical and computational techniques such as linear programming, dynamic pricing algorithms, and machine learning to optimize pricing strategies for maximum profit and adapt to market changes. However, the economic aspect of using communication technologies should not be viewed solely from a commercial perspective. The costs incurred while establishing communication with maritime signaling facilities often serve the interest of public safety and navigation security at sea.

In this paper, the importance of the financial cost incurred during the use of each technology is recognized and analyzed. The results of the analysis concerning each communication technology were categorized as “low cost” (L) or “high cost” (H), which were incurred during its use. Papers in which cost-level data were not recorded (marked as “n/a”) were also considered in the analysis. Table 5 presents the cost analysis results and the corresponding paper references.

From

Table 6. The results of the cost analysis for the application of each technology.

AIS		LoRa WAN
Cost (H/L)	Ref.	Cost (H/L)	Ref.
n/a	[36]	L	[40]
L	[37]	L	[56]
n/a	[38]	L	[41]
-	-	n/a	[51]
-	-	L	[53]
-	-	L	[44]
-	-	L	[45]
-	-	n/a	[44]
-	-	L	[47]
-	-	L	[39]
-	-	L	[48]
LTE		3G
Cost (H/L)	Ref.	Cost (H/L)	Ref.
L	[49]	L	[57]
GPRS		NB-IoT
Cost (H/L)	Ref.	Cost (H/L)	Ref.
L	[50]	n/a	[56]
L	[57]	L	[55]
L	[51]	L	[39]
L	[52]	-	-
L	[53]	-	-
n/a	[54]	-	-
VHF		MaxStream
Cost (H/L)	Ref.	Cost (H/L)	Ref.
L	[57]	n/a	[24]
GSM		ZigBee
Cost (H/L)	Ref.	Cost (H/L)	Ref.
H	[58]	L	[62]
n/a	[59]	L	[55]
H	[60]	-	-

, analyzing the selected papers, it can be inferred that the highest economic cost was recorded when using GSM communication technology. The lowest economic cost was observed when using LoRa WAN communication technology. The analyzed papers did not explicitly state the economic cost of MaxStream communication technology.

The unavailability of specific numerical values describing “H” and “L” is present, similar to the section on electrical power consumption, which also represents a limitation in the analyzed papers. Additionally, the financial cost was not addressed in seven analyzed papers (21.87%). It is important to notice that the financial cost of communication technology is an important aspect of understanding its impact and feasibility. Considering costs makes it possible to assess the economic viability and sustainability of implementing these technologies.

By observing the conducted analysis, it is evident that using “L” and “H” to represent power consumption levels without specific numerical values does present a limitation in the analyzed papers. Without specific values, it becomes challenging to quantify and compare the power consumption across different technologies precisely. By incorporating specific numerical values, the analysis can provide a more comprehensive understanding of the power consumption patterns and enable more precise comparisons and conclusions to be drawn. To avoid these limitations, it is necessary to incorporate standardized measurement methods and utilize machine learning and other analytical techniques to predict system performance under various conditions. We believe that these steps would significantly improve the quality and reliability of future research in this field.

3.6. Standards and Regulatory Requirements

Furthermore, discussing the standards and regulatory requirements related to maritime signaling facilities and communication in maritime areas is crucial. First and foremost, it is necessary to mention IALA. IALA (The International Organization for Marine Aids to Navigation) is an intergovernmental organization aimed at improving the safety of maritime navigation by providing guidelines and standards for aids to navigation [83,84]. Another important organization in this context is the IMO (International Maritime Organization). The IMO is a specialized agency of the United Nations responsible for developing and implementing international rules and standards in the maritime industry [85]. In the context of standards, attention must be paid to RTCM (Radio Technical Commission for Maritime Services) [86]. RTCM is an organization that develops standards for maritime communication and navigation systems, and the standards prescribed by RTCM are used in various naval systems, including Automatic Identification Systems (AIS), navigation tools, ship tracking systems, and real-time data transmission.

Table 7. Comparison of the analyzed technologies and regulatory requirements.

Technology	In Accordance with			Analysis	References
	IMO Requests	IALA Guidelines	RTCM Standards
AIS	YES	YES	YES	Wide range, high costs. It is a standardized part of GMDSS, but energy-intensive.	[23,36,37,38,39]
LoRaWAN	PARTIALLY	YES	NO	Low consumption and cost-effective, but limited range in urban areas.	[40,41,42,43,44,45,46,47,48]
LTE	NO	PARTIALLY	NO	It has an extremely long range (100 km) and fast data transmission, but high energy consumption.	[49]
GPRS	PARTIALLY	NO	NO	Stable data transmission, low energy consumption and cost, but limited range.	[50,51,52,53,54]
NB-IoT	NO	PARTIALLY	NO	It is long-range and energy-efficient, but requires infrastructure that is not always available.	[55,56]
3G/VHF	PARTIALLY (VHF: YES)	PARTIALLY (VHF: YES)	NO	A hybrid of two technologies: VHF, which has an exceptional range (120 km) and low energy consumption, and 3G technology, which is energy-intensive.	[57]
Max-Stream	NO	NO	NO	Minimal range (1 km), suitable for local pilot projects but not for broad implementation.	[24]
GSM	YES (PARTIALLY)	NO	YES	A reliable system for message transmission, but high costs and energy consumption.	[50,58,59,60,61]
ZigBee	NO	NO	NO	Suitable for local applications with low costs and energy consumption, but with a range of only 430 m.	[62]
5G-NR	YES (PARTIALLY)	YES (PARTIALLY)	NO	5G-NR offers high data transfer speeds and low latency, making it suitable for future maritime applications. However, it is still in the implementation phase, and its use in the maritime sector is limited by infrastructure availability.	[19,87,88,89]
VDES	YES	YES	YES	VDES is an advanced version of AIS that offers higher data bandwidth and two-way communication. It is suitable for future maritime applications but requires additional infrastructure and modernization of existing systems.	[65,66,67]
Iridium	YES	YES	YES	The Iridium system is costly, with limited bandwidth and slower transmission than 5G and LTE. Signal quality depends on satellite position and weather, causing occasional interruptions. Its reliability can vary due to full reliance on satellites.	[64]

provides a comparative overview of the analyzed technologies and regulatory requirements.

Based on the analysis presented in Table 7, several key conclusions can be drawn regarding the compliance and suitability of various communication technologies with regulatory requirements. While AIS, VHF, VDES, and Iridium fully comply with IMO regulations, IALA guidelines, and RTCM standards, their practical implementation is hindered by significant technical limitations, including high operational costs, substantial energy consumption, and infrastructure requirements. As a result, despite their regulatory compliance, these technologies are less suitable for large-scale deployment in maritime signaling facilities [65,66,67]. On the other hand, LTE technology offers excellent technical characteristics but requires further standardization within the maritime industry, while LoRaWAN provides good economic and energy efficiency but needs adaptation to meet the standards. GPRS and ZigBee are suitable for local applications with low energy consumption but are currently not developed enough for broader applications under existing regulations. Max-Stream is limited to specific pilot project scenarios, while GSM, although reliable, is inadequate for modern requirements due to high costs and energy consumption. Finally, NB-IoT, although technically promising, is not compliant with IMO requirements and only partially aligns with IALA recommendations, while its infrastructure for implementation is unavailable.

4. Conclusions and Directions for Future Work

Considering the importance of establishing wireless communication with maritime signaling facilities, a systematic review paper was developed to provide an overview of the research area’s current state. The paper was developed following the PRISMA 2020 guidelines and analyzed 29 relevant papers published between 2003 and 2023. It has to be emphasized that this research conducted an extensive analysis of ten communication technologies, including AIS, LoRa WAN, GPRS, NB-IoT, GSM, LTE, 3G, VHF, MaxStream, and ZigBee, with a specific focus on the technical characteristics of communication technologies, which relate to the signal range, electricity consumption, and use cost.

The proven analysis suggests that AIS, LoRa WAN, and NB-IoT are the most effective communication technologies for transmitting data from maritime signaling facilities over long distances. Among these, LoRa WAN is the most energy-efficient technology, consuming 2.14 times less than AIS and NB-IoT. Also, the analysis results of this review paper showed that LoRa WAN has a 2.25 times lower cost of use than those communication technologies with the lowest cost. Overall, LoRa WAN is the superior technology in both metrics. While LoRa WAN demonstrates technical superiority in energy efficiency and cost, its limited compliance with IMO, IALA, and RTCM regulatory standards highlights the need for further research and adjustments to enable broader application in maritime signaling. However, despite technical limitations such as power consumption, signal range, or operational costs, which make them difficult to apply to maritime signaling facilities, AIS, VDES, VHF, and Iridium are the only technologies that fully comply with all established regulatory requirements.

After analyzing the relevant papers, it was observed that there were potential deficiencies in the test performed and the approach utilized in the papers that were considered. A unified network deployment and signal transmission approach is necessary to improve measurement reliability. The precise measurement of power consumption and costs for each communication technology is also needed.

Furthermore, the paper’s research is based on a hypothesis that assumed limited availability in the remote monitoring of maritime signaling facilities. After conducting an analysis, the hypothesis has been confirmed. This validation is supported by a methodological approach, where 29 relevant research papers were rigorously filtered and analyzed. Given the limited number of papers found in the WOS, SCOPUS, and GOOGLE SCHOLAR databases, it was necessary to include additional databases where 13 relevant papers were found, constituting almost 45% of the overall number of papers finally analyzed. This review paper analysis required an extensive search beyond conventional databases to ensure comprehensiveness and relevance, while a systematic study on the timeline of communication technology integration is needed to better understand the evolution of these systems and identify key drivers of change.

A comprehensive review of the available literature found that Industry 4.0 has not been mentioned in the context of maritime signaling facilities. Considering this, the authors believe that future research should explore this area. Additionally, attention should be given to improving the compliance of LoRa WAN and similar technologies with regulatory standards, particularly IALA recommendations for maritime signaling facilities. Furthermore, integrating technologies such as NB-IoT and LTE into existing regulatory frameworks could significantly enhance the efficiency and reliability of marine systems. The authors also suggest that, besides reviewing existing communication technologies and their applications in the maritime sector, future research should focus on developing new analytical methods for evaluating and optimizing these technologies. For instance, integrating machine learning for predictive system performance analysis under various maritime conditions could be beneficial. It is also suggested in this paper that the possibility of combining multiple technologies (such as Iridium, VDES, or 5G-NR networks) is explored through advanced multi-criteria analysis methods, which would allow for optimizing communication system selection based on specific maritime applications.