Les R eseaux de Capteurs sans Fil dans l'Internet des Objects

Abstract

With the emerging technology of the Internet of Things (IoT), a huge number of intelligent devices are being connected to the Internet. Wireless Sensor Networks and Cloud computing are the main elements that facilitate the emergence of IoT. Sensors storage capacity and power consumption are among the main challenging issues in IoT. The 2.4 GHZ band autho- rizes many di erent wireless technologies to exploit the same spectrum, which yields a severe interference environment. The IEEE 802.15.4 proposed the Time Slotted Channel Hopping (TSCH) designed for low-power and lossy networks (LLNs). The TSCH aims to improve the reliability of sensed data transmission by adapting the channel hopping technique to alle- viate the external interference. Because channels can be a ected by Wi-Fi signals, hopping blindly from one channel to another may also deteriorate the data transmission performance. To solve this problem, we propose a new strategy dedicated to TSCH that makes sensors intelligent and enables them to hop channels in a wise manner. TSCH uses shared links to increase the networks' throughput. To ensure collision avoidance in the presence of hidden nodes, this thesis proposes two intelligent algorithms : Time Slotted Channel Hopping with Correct Collision Avoidance backo algorithm(TSCH-CCA) and Enhanced Priority Channel Access Backo Algorithm(E-PCA), applied respectively to both normal packets and critical events packets. Our proposed solution shows signi cant improvements in terms of latency, network congestion, network lifetime, critical event packets lifetime, and collision avoidance. We also proposed two algorithms that overcome the external interference and multi-path fading. These algorithms are called : Enhanced Time Slotted Channel Hopping (E-TSCH) and Reliable Time Slotted Channel Hopping (R-TSCH). To evaluate their performance, we implemented them in Network Simulator 3 (NS3) and compared them to TSCH. The results show signi cant improvements in terms of the retransmitted packets number, packet delivery ratio, and energy consumption. We also proposed three IaaSs on Cloud servers that seek to ensure Load Balancing, minimize the clients latency and provide a fault tolerant system by ensuring critical data availability and achieving fast input and output critical requests.