## 2 Related Studies
\begin{table}
\begin{tabular}{p{22.8 pt} p{22.8 pt} p{22.8 pt} p{22.8 pt} p{22.8 pt} p{22.8 pt} p{22.8 pt} p{22.8 pt}} \hline \hline
**Reference** & **Year** &
\begin{tabular}{c} **Review** \\ **Type** \\ \end{tabular} & **DC** & **Application Types** & **IoT and Architecture Used** & **Challenges \& Issues** & **R. Q.** \\ \hline
[29] & 2017 & SLR & Smart cities &
\begin{tabular}{c} Applications, security, and taxonomy \\ in IoT \\ \end{tabular} & IoT & \(\times\) & \(\times\) \\ \hline
[30] & 2019 & LR & Industrial & \
\begin{tabular}{c} Applications and usage of actuators and sensor networks using MAC protocol. \\ \end{tabular} & IWSN &
\begin{tabular}{c} Security challenges on \\ different layers of the \\ stack, also discussed \\ their solutions \\ \end{tabular} & \(\times\) \\ \hline
[31] & 2016 & LR & – &
\begin{tabular}{c} Technologies, innovations, and applications of IoT discussed. \\ \end{tabular} & IoT & \(\checkmark\) & \(\times\) \\ \hline
[32] & 2014 & LR & Industrial & \
\begin{tabular}{c} Coverage areas of WSN are discussed \\ \end{tabular} & WSN &
\begin{tabular}{c} Challenges they face were: \\ Node type, depth type, \\ communication range, etc. \\ \end{tabular} & \(\times\) \\ \hline
[33] & 2016 & SUR & Industrial &
\begin{tabular}{c} Applications of intrusion detection system in IoT \\ \end{tabular} & IoT & \(\times\) & \(\times\) \\ \hline
[34] & 2015 & SUR & Industrial &
\begin{tabular}{c} Only explore and analyze existing solution to detect sinkhole attack \\ \end{tabular} & WSN & \(\times\) & \(\times\) \\ \hline
[35] & 2020 & LR & – & \(\times\) & Both &
\begin{tabular}{c} Discuss attacks in IoT ans \\ WSN with their solutions, \\ advantages, and limitation \\ \end{tabular} & \(\times\) \\ \hline
[36] & 2021 & SLR & Smart mobiles &
\begin{tabular}{c} Routing attacks and security measures \\ in mobile network are discussed \\ \end{tabular} & WSN & \(\times\) & \(\times\) \\ \hline
[37] & 2021 & LR & Industrial &
\begin{tabular}{c} Detection of wormhole in both domains \\ \end{tabular} & Both & \(\times\) & \(\checkmark\) \\ \hline
[38] & 2017 & SUR & IoT systems &
\begin{tabular}{c} Software board and chips, crypto \\ algorithms, security of IoT systems, and network protocols are discussed \\ \end{tabular} & IoT & – & \(\times\) \\ \hline
[39] & 2015 & SUR & – &
\begin{tabular}{c} Existing security approaches of IoT system are described \\ \end{tabular} & IoT & \(\checkmark\) & \(\times\) \\ \hline
[40] & 2016 & SUR & – &
\begin{tabular}{c} Deployment models for sensor network to achieve coverage, their classification and working was discussed \\ \end{tabular} & WSN & \(\times\) & \(\times\) \\ \hline
[41] & 2018 & BLR & \begin{tabular}{c} Smart factory \\ \& Industry \\ \end{tabular} & \
\begin{tabular}{c} Discuss 12 approaches of Industry \\ 4.0. in business and account management fields \\ \end{tabular} & IoT & \(\times\) & \(\times\) \\ \hline This Paper & 2021 & SLR &
\begin{tabular}{c} Smart industry \\ and Factory \\ \end{tabular} & Applications and contribution of both IoT and WSN are discussed in detail & IoT and (both) & WSN & Key challenges and open issues of both IoT and WSN in Industry 4.0 & \(\checkmark\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._applications and advantages of WSN being deployed everywhere due to their flexible and dynamic nature. They discussed each application of WSN in urban areas and their solutions. They analyzed how WSN deployment in urban areas demanded much more care and attention due to harsh weather and perverse channel conditions. WSN is applicable in many domains, such as industrial automation, and the requirement elicitation of the industrial process is different from general WSN requirement gatherings. In [17], the authors presented some standard protocols that were used to measure the requirements of industrial applications. They also provide solutions to WSN protocols by discussing MAC, routing, and transport in detail.