# Unveiling LoRa's Oceanic Reach: Assessing the Coverage of the Azores LoRaWAN Network from an Island
## 1 Introduction  
The Internet of Things (IoT) can be described as a network of machines, sensors, actuators, and physical devices that can interact with each other and their environment, collecting information and transferring data to the network without any human interference, connecting the physical and digital worlds [1]. The IoT has proliferated in recent years, finding applications in various industries, such as energy, health, logistics, security, and agro-industry [2]. The maritime sector also exploits IoT [3], focusing mainly on logistics [2]. However, IoT applications can also be applied to maritime and marine activities such as aquaculture, offshore platforms, ocean exploration, fishing vessels and generic maritime monitoring [4, 5, 6]. Additionally, it may also be applied to fishing gear and touristic activities. In these contexts, reliable low-power machine-to-machine communication presents one of the biggest challenges. Recently, significant advances have been made regarding wireless communications, specifically with the introduction of the sixth generation (6G). This type of communication, more specifically the fourth and fifth generation, 4G and 5G, respectively, has shown excellent results in terrestrial IoT applications. However, when the communication environment is maritime, there are many challenges [7] rooted in this type of environment, namely large distances with a low density of users. In the case of wireless communications (4G and 5G), base stations are not installed in the sea, which, allied to their relatively short radius of coverage, restricts their usage to onshore and coastal scenarios. In this case, communicationcannot be established between vessels or vessels and land, and therefore, the application of IoT in the maritime/marine environments will remain limited to uses within a ship. A set of technologies that are used or expected to be used in maritime communications was identified by [8; 9]. Satellites like Argos, Iridium, or Iridium NEST are considered a pillar of maritime communications, mainly used for long-range communication scenarios. However, this technology is associated with high costs and bandwidth limitations. Most medium and short-range ship-to-ship or ship-to-shore communication technologies use the radio frequency (RF) band, more specifically, medium frequency (MF), high frequency (HF), very high frequency (VHF), and ultra-high frequency (UHF) bands. However, although these technologies can reach long propagation distances, they only provide small data rates, limiting their applicability to basic scenarios. In addition to using the RF band, the infrared band is also used. This, together with optical sensors, creates a solution known as free space optics (FSO), capable of providing connectivity to maritime communication networks. However, the FSO signals can be affected by weather and sea conditions, eventually creating variations in the optical signals or the plane of the receiver (vessel). Mobile communications (GSM) or WiMAX technology are also used in maritime scenarios. Recently, a solution based on unmanned aerial vehicles (UAVs) was proposed to improve the coverage of terrestrial-satellite communication networks [10]. Although the technologies mentioned above are used in maritime communications, their power requirements can only be met with access to an electric grid or a powerful energy source. With these technologies, the power needed for the communications module is often several orders of magnitude larger than that of the sensors. Less energy-intensive communications would allow sensing the environment more autonomously and for longer periods. For example, sensors could measure and communicate for long periods with a small battery. Lately, Low Power Wide Networks (LPWANs) have been widely used in monitoring applications in several areas.