# Democratization of PV Micro-Generation System Monitoring Based on Narrowband-IoT
## 2 Communications: NB-IoT  
Low-power, wide-area (LPWA) technologies are targeting most emerging markets and applications. LPWA is a recent generic term involving different technologies focused on enabling wide area communications, minimizing power consumption and cost [28]. LPWA has become a relevant growing space in IoT since in general LPWA solutions are perfectly suitable for such IoT applications that only need to transmit low amounts of data over a long range. Other researchers proposed a ZigBee network tested with WiFi for smart grid applications. However, these tools have limited capability for analyzing real scenarios and, according to [PERSON] et al. [29] ZigBee uses the same frequency band as WiFi, which can lead to potential radio interference. Consequently, most of the developed LPWA technologies have arisen in both unlicensed and licensed markets, such as SigFox, LTE-M, NB-IoT and long range (LoRa). Among them, [PERSON] et al. [30] affirmed that NB-IoT and LoRa solutions are the two leading emergent technologies,despite the important technical differences in terms of network architecture, physical features and MAC protocol between them. Table 1 compares different network schemes and communication technologies. Recently, different comparative studies are available in the specific literature evaluating LoRa and NB-IoT technologies [31]. Examples of new network architectures combining both technologies can be found in [32; 33]. In terms of vulnerabilities, LoRaWAN and NB-IoT give sufficient security guarantees, but according to [PERSON] et al. [34] both technologies need to be properly enforced. The NB-IoT technology was standardized in 2016 by the Third Generation Partnership Project (3 GPP), considerably increasing the NB-IoT applications for wireless data communication purposes [35]. In addition, the presence of NB-IoT modules in the IoT device market share by 2030 will considerably increase too [36]. NB-IoT is compatible with LTE-M, with transmission speed of 150 kbps and a coverage range of 15 km. It is a licensed technology deployed in 79 countries, with an investment of $598 billion [37]. In this case, NB-IoT is selected by the authors for PV power plant monitoring and communication network evaluation. This proposal is in line with other recent network applications, such as Smart Water Grid (SWG) [38], water quality monitoring [39] or sustainable farming irrigation [40]. In all cases, NB-IoT was selected as a suitable candidate due to high scalability in comparison to other technologies, such as LoRaWAN and SigFox. [PERSON] et al. [41] demonstrated that NB-IoT satisfied both qualitative and quantitative requirements in terms of security, reliability and scalability. The relevant presence of IoT-infrastructure devices, the remarkable variety of applications and the use of various data processing solutions have recently led to the fact that traditional data center architectures do not allow the software configuration nor the physical scaling for tasks to be solved. Moreover, they are no longer able to provide the current required indicators focused on stability, controllability or productivity [42]. On the other hand, and regarding industrial applications, [PERSON] et al. [43] concluded that NB-IoT offered the highest quality of service (QoS) while also ensuring data delivery, being a potential replacement to LoRaWAN when communication reliability was a required factor. In addition, NB-IoT was also proposed as an alternative solution for real-time demand response, able to monitor, control and connect electrical appliances [44]. In this paper, we propose an NB-IoT solution for PV power plant monitoring and communication purposes focused on self-consumption installations. Our approach is in line with recent contributions focused on PV installations [45; 46; 47].