# Toward QoS Monitoring in IoT Edge Devices Driven Healthcare--A Systematic Literature Review
## 6 Analysis of SLR Results
### Paper Distribution  
The papers were categorized based on the study's goals and the year they were published as shown in Figure 14. Additionally, a citation analysis is performed to determine the current rate of research effort in the QoS of SHAs.  
The pie chart illustrates the quantity of recently released filtered research publications. The fact that more than half of the articles were released in 2020 and 2021 shows how much the research community has recently been interested in QoS-related issues in SHAs.  
Figure 14: Article distribution according to year of publication.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Ref.** & \
\begin{tabular}{c} **Review** \\ **Type** \\ \end{tabular} & **Main Topic** & **Year** & **Covered** & **Pre-SLR** & **Criteria** &
\begin{tabular}{c} **Papers** \\ **Screened** \\ \end{tabular} & **RQs** & **QoS** \\ \hline
[35] & SLR & IoMT & 2022 & 2005–2020 & NA &
\begin{tabular}{c} Citation \\ Impact factor \(\geq 1\) \\ \end{tabular} & 135 & Not clear & NA \\ \hline
[36] & SLR & IoT & 2022 & 2015–2022 & NA & Keywords & 106 &
\begin{tabular}{c} Reasons \\ constraints \\ solutions \\ \end{tabular} & Cost \\ \hline
[37] & SLR & IoT & 2022 & 2015–2021 & NA &
\begin{tabular}{c} Quality \\ assessment score \\ \end{tabular} & 22 & IoT adoption & NA \\ \hline
[38] & SLR & \
\begin{tabular}{c} IoT \\ AI \\ \end{tabular} & 2022 & 2016–2021 & NA &
\begin{tabular}{c} Citation count \\ impact factor \\ journals \\ \end{tabular} & 104 & E-Cardiac & NA \\ \hline
[39] & SLR & IoT & 2021 & NA & NA & Keywords & 81 &
\begin{tabular}{c} Edge \\ computing \\ Blockchain \\ \end{tabular} & NA \\ \hline
[40] & Survey & Blockchain & 2019 & NA & NA & Keywords & NA & NA & NA \\ \hline
[41] & PRISMA & ML & 2022 & 2016–2021 & NA & Keywords & 50 &
\begin{tabular}{c} Smart \\ Technologies \\ \end{tabular} & Network \\ \hline
[42] & PRISMA & \begin{tabular}{c} Smart \\ Healthcare \\ \end{tabular} & 2022 & 2015–2021 & NA & Geographical & 26 & \begin{tabular}{c} Adoption \\ challenges \\ \end{tabular} & NA \\ \hline Our & Hybrid & \begin{tabular}{c} QoS \\ Optimization \\ \end{tabular} & 2023 & 2018–2023 & Mentioned & \
\begin{tabular}{c} Recent keywords’ \\ frequency \\ \end{tabular} & 60 &
\begin{tabular}{c} Optimization \\ issues \\ \end{tabular} & Optimization \\ \hline \hline \end{tabular}
\end{table}
Table 3: Comparative evaluation of the examined publications using basic SLR criteria.  
Figure 15 displays the distribution of research articles by study methodology. Studies that used simulations predominated, followed by publications and surveys that had an experimental focus. Simulator-based papers were those that simply employed simulators, whereas experimental-based papers included some or all hardware interfacing. Finding review or survey articles proved challenging. This distribution demonstrates the QoS research direction for the smart healthcare system. Furthermore, the dearth of review publications points to the necessity of SLR in this area of research.  
A citation analysis was also conducted, as shown in Figure 16, to evaluate the impact of selected works on the research community and body of knowledge. Although it was not the most popular piece, the most-cited article was published in 2018. On the other hand, the most well-liked piece was released later, in 2020, and garnered fewer citations. The article that had the least number of views and citations was the one that appeared first, in 2017. As indicated by increasing views but relatively limited published research output and consequently fewer citations, this trend shows that the research community has begun to pay greater attention to QoS issues in smart healthcare.