## 6 Conclusions  
The article demonstrated that the use of IoT in conjunction with mobile telecommunications technologies can support critical infrastructure networks. Utilizing simulation and experimental scenarios, the paper culminates in the affirmation of the proposed platform's capacity to furnish secure voice services and data transmission, while also hinting at the potential for hybrid communication networks integrating LPWAN, Wi-Fi, and BLE technologies [2]. Implementing a private 4G LTE network using SDR technology proved \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Device** & **Ping** & **Download** & **Upload** & **Jitter** \\ \hline UE[1] & 51 ms & 17.74 Mbps & 4.72 Mbps & 9 ms \\ UE[2] & 58 ms & 18.32 Mbps & 5.34 Mbps & 13 ms \\ \hline \hline \end{tabular}
\end{table} 
Table 14: SpeedTest results. to be feasible, covering the needs of critical networks with VoLTE capability and access to websites and videos. The use of open-source software and the Linux operating system (OS) enhanced the low-cost implementation, while SDR technology emerged as a significant advancement due to its low cost and flexibility. Finally, the OAI platform provided all the necessary tools for the study's implementation. Focusing on the simulation and experimental scenarios, we conclude that the proposed experimental platform network setup can provide secure voice services and data transmission in a specific area. The article meticulously delineates the system's capabilities, encompassing the transmission of sensor data, images, videos, and real-time video calls, all while upholding stringent mobile network security standards. Therefore, the proposed experimental platform, in addition to ECSs, may help researchers and developers cover a multitude of communication applications, as below:  
* In rural, private, and isolated areas with limited Wi-Fi coverage, a private network of wireless sensors with the possibility of calls could be very useful, enabling workers' direct communication, while enabling real-time status monitoring of the products. * For patients in intensive care units (ICUs) and other clinics in hospitals, a wireless sensor network, including wearable devices, can be realized, in collaboration with the private network, to transfer patients' heart rate, oxygen data, and other vital data on a 24 h basis in a central system to which doctors and nursing staff have immediate access, while patients and attendants will be able to call them for immediate help by pressing a button. Moreover, we can build early warning systems (EWSs) based on sensor networks [34]. * In critical event situations on ships located far from the land, using a suitable digital signage application, safety personnel could guide passengers to muster stations by taking the least dangerous route. Moreover, an entire network of wireless sensors can also be created, along with the private network, to help ship managers monitor the ship's system in real-time [35]. We plan to extend our communication network by adding a second 4G/LTE base station and testing the VoIP application under variable circumstances. Moreover, we plan to install amplified base stations into cars with variable height antenna masts, thus improving their gain and making them more flexible. This improvement will allow us to test the experimental platform inside critical infrastructures and larger off-grid areas. Furthermore, we will expand our network by adding an isolated LoRaWAN subnetwork for sensor monitoring and data gathering [2]. At the same time, we will continue conducting simulation tests using the OMNeT++, and MATLAB tools to improve the scalability of the on-premises network and its QoS. We will also conduct more experiments in variable terrains using video calling and image transfer applications, testing at the same time network viability by scheduling network attacks and extracting security reports.