Design and Development of a Distributed Mininet-WiFi for IoFT Communication Network Performance Analysis

In recent years, the ICT sector has been playing a key role in the growth of the smart city concept through the widespread application of IoT devices. This evolution is mainly driven by the spread of wireless networks, which have enabled wireless communication between heterogeneous machines via the Internet. However, the coverage of these wireless networks is still limited and needs to be extended in peripheral areas where routers and access points are not installed. This problem is extremely aggravated in the case of geographical constraints and natural disasters, where the wireless network could fall taking an entire area offline. To partially solve these critical situations, the research community has recently proposed the creation of a network of IoFT objects called Unmanned Aerial Vehicles (UAVs) capable of covering hard-to-reach areas. UAVs could become wireless network access points that fly freely in space, providing mobility and reduced costs compared to centralized infrastructure. To enable this flexibility in wireless networking, it is cost-effective to use decentralized mesh networking protocols that offer adaptability to mobile networks, where changes in topology can affect the network connectivity. In this field, several challenges impose constraints on UAV networks. For instance, the limited battery capacity of UAVs dictates the implementation of low-power software strategies. Second, on-board memory and computing power are limited, so routing algorithms must be relatively simple. Finally, because a wireless mesh network has no central infrastructure, security and resilience against cyber threats must be addressed in the design phase. Therefore, it is essential to conduct tests to evaluate the performance of the UAV mesh network before deploying it. This thesis focuses on the development of a distributed simulation tool that can enable the emulation of a wireless network without the difficulties, costs, and complexities of implementing a real hardware infrastructure. The chosen enabling technology is Mininet-WiFi, an open-source wireless network emulator that facilitates the design of wireless networks with a simple programming interface. By following an efficient emulation strategy, mesh networks can be tested in a standalone computer by leveraging operating system kernel modules normally used in real-world scenarios. Mininet Wi-Fi was distributed on separate cluster nodes to analyse the performance of different kernel modules of a single emulated wireless node. In this way, different routing protocols and security features can be tested on mesh networks to see which ones lead to better performance. This implementation isolates the emulation of the UAVs from that of the wireless medium performed by the wmediumd application. This is done by implementing standard communication protocols (i.e. TCP and UDP) for managing data exchange among the nodes. The distributed emulation infrastructure was tested on a real UAV mesh network by implementing different mesh routing protocols (i.e. B.A.T.M.A.N. and Babel). The results present several key performance indicators that confirm the comparability of the distributed Mininet Wi-Fi implementation to the standalone version without introducing significant reduction in latency and bandwidth, enabling the kernel modules and software performance analysis of the different mesh routing protocols implemented in the proposed scenario.