## 11 Current Studies and Future Directions
### Research Directions
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Ref.**} & \multicolumn{4}{c}{**Key Enabling Technology**} & \multicolumn{4}{c}{**Distributed Edge Computing**} & \multirow{2}{*}{**KPI**} & \multicolumn{2}{c}{**Smart City Application**} \\ \cline{2-13}  & **IoT** & **Blockchain** & **SDN** & **NFV** & **UAV** & **AI** & **Fog** & **MEC** & & & \\ \hline \multirow{3}{*}{[121]} & \(\surd\) & \(\times\) & \(\surd\) & \(\times\) & \(\times\) & \(\times\) & \(\times\) & \(\surd\) & \(\times\) & \(\bullet\) & Connectivity & Intelligent transportation systems (ITSs) \\ \cline{1-1}  & & & & & & & & & & & & \(\bullet\) & Latency & Parking and monitoring system \\ \cline{1-1}  & & & & & & & & & & & & & & \\ \cline{1-1}  & & & & & & & & & & & & & & \\ \cline{1-1}  & & & & & & & & & & & & & & \\ \hline \multirow{3}{*}{[122]} & \(\surd\) & \(\times\) & \(\times\) & \(\times\) & \(\surd\) & \(\times\) & \(\times\) & \(\surd\) & \(\times\) & \(\bullet\) & Bandwidth & Air monitoring \\ \cline{1-1}  & & & & & & & & & & & & & & \\ \cline{1-1}  & & & & & & & & & & & & & & \\ \hline \multirow{3}{*}{[123]} & \(\surd\) & \(\times\) & \(\times\) & \(\surd\) & \(\times\) & \(\times\) & \(\surd\) & \(\times\) & \(\bullet\) & Bandwidth & Air monitoring \\ \cline{1-1}  & & & & & & & & & & & & & & \\ \cline{1-1}  & & & & & & & & & & & & & & \\ \hline \multirow{3}{*}{[124]} & \(\surd\) & \(\times\) & \(\times\) & \(\surd\) & \(\times\) & \(\times\) & \(\surd\) & \(\times\) & \(\bullet\) & Network congestion & General \\ \cline{1-1}  & & & & & & & & & & & & & & \\ \cline{1-1}  & & & & & & & & & & & & & \\ \hline \multirow{3}{*}{[125]} & \(\surd\) & \(\surd\) & \(\surd\) & \(\surd\) & \(\times\) & \(\times\) & \(\times\) & \(\surd\) & \(\bullet\) & Energy consumption & & \\ \cline{1-1}  & & & & & & & & & & & & & \\ \hline \multirow{3}{*}{[126]} & \(\surd\) & \(\times\) & \(\times\) & \(\times\) & \(\times\) & \(\times\) & \(\times\) & \(\times\) & \(\bullet\) & No evaluation & Military operations \\ \cline{1-1}  & & & & & & & & & & & & & \\ \hline \multirow{3}{*}{[127]} & \(\surd\) & \(\times\) & \(\times\) & \(\surd\) & \(\times\) & \(\times\) & \(\times\) & \(\times\) & \(\bullet\) & Scalability & Smart parking \\ \cline{1-1}  & & & & & & & & & & & & & \\ \cline{1-1}  & & & & & & & & & & & & & \\ \cline{1-1}  & & & & & & & & & & & & & \\ \cline{1-1}  & & & & & & & & & & & & & \\ \hline \multirow{3}{*}{[128]} & \(\surd\) & \(\times\) & \(\surd\) & \(\times\) & \(\times\) & \(\times\) & \(\surd\) & \(\surd\) & \(\bullet\) & Processing delay & Smart transportation \\ \cline{1-1}  & & & & & & & & & & & & & \\ \hline \multirow{3}{*}{[129]} & \(\surd\) & \(\surd\) & \(\times\) & \(\surd\) & \(\times\) & \(\surd\) & \(\times\) & \(\times\) & \(\bullet\) & Security & Smart grid \\ \cline{1-1}  & & & & & & & & & & & & & \\ \hline \end{tabular}
\end{table} 
Table 17: _Cont._data integrity, identifying and mitigating potential issues, including data corruption and tampering. This increases the reliability of communications over smart cities in a way that meets the 5G demands. Another direction is the development of adaptive machine learning models that can change with smart city settings as they change. This means that the models should keep learning and adjusting based on new data to work in dynamic circumstances. In addition, this direction can include AI/ML algorithms that prioritize important data flow, guaranteeing that critical services receive the necessary bandwidth and resources during instances of heightened demand. Also, AI/ML algorithms can assist in developing QoS schemes that adaptively modify data prioritization according to the real-time demands of various applications. Furthermore, AI/ML can increase the network availability of smart city applications. AI/ML algorithms can be used for predicting potential network failures or disruptions, allowing for proactive measures to maintain network availability. This meets the novel demands of zero-touch networks that can assist many smart city applications.