## 3 LoRaWAN Background
### LoRa/LoRaWAN SWOT Analysis  
Table 2 presents the SWOT analysis for LoRa/LoRaWAN in the context of this work. Other interesting works in the literature present SWOT analysis for LoRaWAN from a general point of view [41] and in the context of smart cities [79].  
Figure 3: Timing of a Class A ED transmission (redrawn from [39]).  
LoRaWAN is considered one of the most successful LPWAN technologies [86; 87; 41]. As Table 2 shows, the main strengths of LoRaWAN are that it offers cheap EDs with long battery lifetime and the possibility to easily develop private networks. Other strengths include the large coverage (up to 15 km in outdoor environments [79]). Among the weaknesses, it is known that the bit rates supported by LoRaWAN are limited, therefore LoRaWAN is not recommended for applications that require high bit rates. In addition, as it was discussed in Section 3.4 uplink communications are strongly favored for Class A EDs, therefore they are not suitable for bidirectional communications. A weakness is represented by the limitations of the plain ADR algorithm when it works with mobile EDs. However, some works in the literature [80; 81] propose promising alternative ADR algorithms to cope with this limitation.  
The lack of support for industrial communications is because the uncoordinated channel access mechanisms supported by LoRaWAN cannot provide bounded delivery times to real-time messages. However, some existing works in the literature [82; 83; 84] proposed techniques that enable predictable communications over LoRa leveraging TDMA-based channel access.  
As LoRaWAN operates in unlicensed bands the main threat is the outside interference, therefore techniques to quantify and alleviate it should be considered in the future. Another potential threat is represented by the competing IoT LPWAN technologies [88], such as Sigfox and NB-IoT. However LoRaWAN offers a higher bit rate than Sigfox and, differently from NB-IoT, which uses licensed frequency bands, operates in the license-free spectrum. Using LoRaWAN, differently from Sigfox and NB-IoT, there is no need for subscription and this reduces the operating costs especially for dense IoT deployments. Moreover, as mentioned in the Opportunities, some technology-agnostic solutions could leverage the convergence of multiple technologies to improve the offered services. Moreover, the interest  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Strengths** & **Weaknesses** \\ \hline Large coverage (up to 15 km in outdoor environments [79]) & The plain ADR algorithm does not work well with mobile EDs and performs badly under heavy network load \\ Long battery lifetime (more than 10 years [79]) & Not suitable for bidirectional communications (mainly for Class A EDs) \\ Cheap EDs (less than $100) [79] & Lack of predictability for industrial communications \\ Private network deployment possible & Unsuitable for applications that require high bit rate \\ Easy network deployment and configuration & \\ \hline \hline
**Opportunities** & **Threats** \\ \hline State-of-the-art literature provides ADR algorithms for mobile & Interference from other technologies in the ISM band \\ EDs, e.g., [80; 81] & Strong competing IoT LPWAN technologies are available, e.g., \\ State-of-the-art literature provides novel channel access & Sigfox and NB-IoT \\ strategies that offer support for real-time flows over LoRa, & \\  e.g., [82; 83; 84] & Strong competing IoT LPWAN technologies are available, e.g., \\ Big IT enterprises are developing or supporting LoRa products & \\ (e.g., STMicroelectronics, Cisco, IBM, Intel) & \\ \hline \hline \end{tabular} Novel technology-agnostic solutions on the market offer improved services through the convergence of connectivity, e.g., combining LoRaWAN and Sigfox for more accurate vehicle location services [85]  
\end{table}
Table 2: SWOT analysis of LoRa/LoRaWAN.  
of big Information Technology (IT) companies in developing or supporting LoRa products paves the way for the growth and establishment of a rich LoRa/LoRaWAN ecosystem.