# Fog Computing Enabling Industrial Internet of Things: State-of-the-Art and Research Challenges
## 6 Open Research IIoT Application Domains, Fog Computing as an Enabler  
In Industry 4.0, the digital transformation of the industry requires research development in all fields (smart city, D2D communication, transportation, healthcare, etc.). These all IIoT domains have same critical issues in communication and networking. Even though, fog computing has unputeenth applications in multiple research areas, few notable applications in respective of IIoT domain have been listed in Table 1 to gain an idea about the diverse use of fog computing. The main objective is achieving maximum benefits/solutions using fog computing for this industrial revolution at efficient optimized QoS measurements. Many authors have proposed solutions in past years to networking and communication challenges in order to leverage benefits using fog computing in all domains of IIoT. Some has started to provide prototypes for supporting their research, Table 2 has listed some case studies for various areas of open research. In this section, some of the past research works are summarized for readers to get an idea about the integration of fog computing with different pre-existing network architectures. This integration brings solutions to support IIoT applications, yet there are many open research areas in all fields that need to be solved in the coming future towards the industrial development. \begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline
**Ref. No** & **Iiot Application Domain** & **R.A** & **L** & **E** & **T/R/C** & **Cc** & **P** & **H** & **B** & **S** & **TL** & **Architecture** \\ \hline
[49] & Mobility & & & & & & ✓ & & Routing & SDN \\
[50] & Big Data Analytics & ✓ & ✓ & & & & & & Routing & HeNets \\
[51] & Smart IoT devices & ✓ & ✓ & & & & & Downlink & Cloud Computing \\
[52] & Smart IoT devices & ✓ & & & & ✓ & & Downlink & RANs \\
[53] & Big Data Analytics & ✓ & & & & ✓ & & Downlink & NOMA+RANs \\
[59] & VANETs & ✓ & & & & & & Downlink & Cloud Computing \\
[61] & Healthcare & ✓ & ✓ & & & & ✓ & Downlink+Uplink & Cloud Computing \\
[62] & Smart IoT devices & ✓ & ✓ & & & ✓ & & Downlink & Fog-IoT \\
[69] & 5G network & ✓ & ✓ & & ✓ & & Downlink & NFV+RANs \\
[72] & Virtualized Passive Optical Networks (VPCM)/5G & ✓ & & & ✓ & & Downlink+Uplink & RANs + Cloud Computing \\
[77] & Small Cell Networks (SCN)/5G & ✓ & & ✓ & & & & & \\
[78] & 5G network & ✓ & & ✓ & ✓ & & Downlink & RANs \\
[79] & 5G network & ✓ & & ✓ & ✓ & & Downlink & Cloud Computing \\
[81] & 5G network & ✓ & & & & ✓ & Downlink & RANs \\
[82] & Heterogeneous IoT applications & ✓ & & & & ✓ & & & \\
[102] & VANETs & ✓ & & & & & & & \\
[84] & Smart monitoring systems & ✓ & & & & & & & \\
[85] & Security & ✓ & & & ✓ & & & Routing & VN+Cloud Computing \\
[87] & Heterogeneous IoT applications & ✓ & & & ✓ & & & & \\
[88] & Time-sensitive IoT applications & ✓ & ✓ & & & & & \\
[89] & Heterogeneous IoT applications & ✓ & ✓ & & ✓ & & & \\
[93] & Wireless network & & & & ✓ & ✓ & & & \\
[94] & & & & ✓ & ✓ & & & \\
[95] & 5G network & ✓ & & & ✓ & & & \\
[103] & Microgrid & ✓ & ✓ & & ✓ & & & \\
[104] & Security+Microgrids & & & & ✓ & & & \\
[105] & Microgrid & ✓ & ✓ & & ✓ & & & \\
[101] & Smart city & ✓ & ✓ & & & & & \\
[92] & Smart city & ✓ & ✓ & & & & & \\
[106] & Multimedia & ✓ & ✓ & & ✓ & & & \\
[107] & Secure and time saving multimedia & ✓ & & & & & & \\
[108] & Secure IoT applications & & & & ✓ & & Downlink & \\
[109] & & & & & ✓ & & & \\
[110] & 5G mobile network+V2G services & ✓ & & & & & & \\
[111] & VANETs & ✓ & & & & ✓ & & \\ \end{tabular}
\end{table} 
Table 1: Literature Review: R.A-Resource Allocation, L=Latency, E=Energy, T/R/C=Throughput/Rate/Capacity, Cc=Cache, P=Power, H=Handover, B=Bandwidth, S=Security, T.L=Transmission Link.