## 6 Future Challenges and Open Research Issues
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline
**Reference** & **Technique** & **WSN-CFS** & **Intelligent Data** & **QuS** & **Multiity** & **Cross Layer** & **Level of** & **Localization** & **IP-Based** & **Energy** & **Applications** \\  & **Specifics** & **Integration** & **Processing** & & & & & & & & & & & & \\ \hline
[81] & IEEE 802.15.4 & & & & Effective Data, & & & & & & & & & & & \\  & Evaluation & & Yes & Yes & Effective Data, & & & & & & & & & & \\  & & & Packet Long Rate, & & & & & & & & & & & & Application (Video, Voice) \\  & & & & & & & & & & & & & & Voice) \\ \hline
[82] & Sensor Grid & Yes & Yes & Yes, Analysis, & & & & & & & & & & & \\  & & & Forecast, Data & & & & & & & & & & & \\  & & & Repository & & & & & & & & & & \\ \hline
[83] & Product Loss & & & Packet Loss, & & & & & & & & & & \\  & Control with & Yes, Integrated & Yes, Prediction & & Mixed Traffic & No & Yes, Platform & Yes, & Network & Yes & Resource & General \\  & Actuation & & & Reliability & & & & & & & & & \\  & & & & Reliability & & & & & & & & & \\ \hline
[84] & Plane Detection & & & Yes, 3-D Data & & & & & & & & & & \\  & & Analysis, Storage & & & & & & & & & & & \\  & DTSCN & & & and Computational & & & & & & & & & \\  & & & Resources & & & & & & & & & \\ \hline
[85] & Aggregate Load & & & Mathematical & Highly Interactive & & & & & & & & & \\  & Modeling Using & & & & & & & & & & & \\  & Data Mining & & & Highly Interactive & & & & & & & & \\  & & & & & & & & & & & & \\ \hline
[86] & Cellular & & & Yes & Yes, Data (Alerts) & Wide Coverage & & & & & & & & \\  & Networking & & & Pre-processing & & & & & & & & \\ \hline  & Pipeline Language & & & & & & & & & & & \\  & & & & & & & & & & & & \\  & & & & & & & & & & & & \\  & & & & & & & & & & & & \\  & & & & & & & & & & & & \\  & & & & & & & & & & & & \\ \hline
[87] & Pipeline Language Detection - & & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: _Cont._The radio link between low-power sensor networks is extremely unreliable due to harsh environments in which they are deployed. In the case of pipeline monitoring, the environment gets even tougher since oil and gas pipelines in desert areas have to bear heat and humidity while pipeline under sea bears huge water pressure. Underground pipelines also present challenges in communication since radio waves at ground level may have to deal with multiple paths. Hence, a reliable communication model for a secure and energy efficient communication between wireless nodes is one of the main research areas for current and future efforts [17]. The need for new, efficient and small sensors for monitoring leaks and quality of fluids like water, oil and gas is increasing. New sensing techniques based on novel approaches for precision and physical phenomenon detection will be able to enhance the monitoring systems' reliability and robustness by eliminating the sensing errors and increasing efficiency [88,89]. The sensing nodes should be able to reconfigure for sensing at different sampling rates and adapt to different conditions and scenarios in order to support the application and ease of monitoring. Research to develop adaptable and configurable wireless nodes for the pipeline monitoring systems is required with growing complexity of sensing information and reliability. It is also important for the system to be scalable with future improvements and enhancements [90]. Finally, scalability for pipeline monitoring systems is a critical issue due to harsh sensing environments, piping structures and difficult terrains. Hence to summarize, major design factors for CPSN applications need to consider physical sensor network type, application security, methods to convert raw data into meaningful information and technology to support seamless data flow (Figure 13).