# Security Vulnerabilities in LPWANs--An Attack Vector Analysis for the IoT Ecosystem
## 2 Systematic Review
The adopted inclusion and exclusion criteria are presented in Table 2.  
After performing all the steps of the systematic process, the results were obtained and presented as a heatmap in Figure 5. These results are expressed in the same three categories defined in the keywords and the queries: Security, Tech, and Smart. As final remarks, it can be highlighted that, since the queries in the \"Security\" and \"Tech\" categories depended on technologies launched around 2015 like LoRa [35] and NB-IoT [18], the results appear after 2015. In the \"Security\" category, the query obtaining a higher number of total papers was the more general query including the _security_ word in the metadata, totaling 95 papers. In this general query, the results jump from 2 papers at the beginning of 2016 to 35 papers, in 2019. The second query with more papers in the \"Security\" category was the query using the _exploit_ word, with a total of 57 papers. The queries related to _defense_, _vulnerabilities_, and _privacy_, obtained the least number of papers, totaling 9, 7, and 6 papers, respectively. For the queries defined under the category \"Tech\", the query with _lora_ counted 89 papers, more than the double of the query in second, that is, it is followed by the query with _nb-iot_, with 42 papers, the one using _lpwan_, with 24 papers, and finally _sigfox_ with only 3 papers. \begin{table}
\begin{tabular}{c c} \hline \hline
**Inclusion Criteria** & **Exclusion Criteria** \\ \hline Papers about LPWAN communication technologies & Papers that are duplicate \\ Papers about LPWAN security & Papers older than 2010 \\ Papers about LPWAN in smart environments & Papers that are not about LPWAN \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Inclusion and Exclusion criteria for this systematic review. Figure 4: Queries defined for each category (“Security”, “Tech” and “Smart”). Regarding the topic \"Smart\", the generic query _smart_ obtained 86 papers, with a maximum in 2019. Within the specific queries including _smart environment_, _smart campus_, and _smart monitoring_, the one that ranked higher numbers was the last, with 25 related works. It was followed by the query including _smart environment_, with 16 works, and finally _smart campus_ with only 2 papers. The results regarding these specific queries are diverse over the years, without a pattern or peak that could be indicative of any factor. The results obtained are important to understand the dynamics around security-related topics and the selected technologies and are highly dependent on: the search engine, the keywords, the queries defined, and the inclusion and exclusion criteria. Given this, the questions initially defined can be answered as follows:  
* **Q1--**Given the technologies LoRa, Sigfox, LPWAN, and NB-IoT, what is the progress in the number of papers published? **Answer**: The first results obtained date from 2016, with 3 research papers, increasing to 57, in 2019. * **Q2--**In the specific range of technologies (LoRa, Sigfox, LPWAN, and NB-IoT), which security-related topics have been addressed by the researchers? **Answer**: Regarding the chosen technologies, the security-related topics addressed were: _attack_ with 16 papers, _defense_ with 9 papers, _exploit_ with 57 papers, _security_ with 95 papers, _privacy_ with 6 papers and _vulnerabilities_ with 7 papers. All results date from the period between 2016 and 2020. * **Q3--**Given a set of security related topics, what are its relation to LPWAN, LoRa, Sigfox, and NB-IoT?\" **Answer**: With the set of security-related topics, the technology that ranked higher was _LoRa_ with 89 papers, starting in 2016 with 2 studies and reaching 34 in 2019. Secondly, we had _NB-IoT_ with a total of 42 papers, starting with 2 studies in 2017, and rising to 17 in 2019. Then, _LPWAN_ scored 24 papers, starting with 1 study in 2016 and achieving 9 in 2018. Lastly, _Sigfox_ presents a total of 3 results, starting with 2 studies in 2019 and finishing with 1 in 2020.