Wireless sensor networks (WSNs) are increasingly invading our daily lives. In the era of Internet of Things, they are used in domains requiring the observation of the physical world and data collection-based applications. However, many of the obstacles inherent to the specificities of  WSNs must be overcome before the maturity of this technology can be reached. Among these obstacles, the limitation of resources such as energy, computing power, bandwidth and memory space of the sensors. In this thesis, we focus on mobility as a solution to improve network performance in terms of energy consumption and optimization of data collection.

A Mobile Wireless Sensor Network  is a network where at least the sink is mobile. First, we focused to the case where only the sink is mobile. In this context, we proposed a network organization that leverages sink mobility to optimize data collection while reducing the energy dissipated by sensors. The proposed organization is based on a grid architecture and an optimized algorithm for moving the sink to visit the cells of the grid and collect the data. We implemented our solution using the NS-2 simulation environment. Our simulation results clearly show the improvement made when compared to other approaches of the state of the art.

We also worked on the case where the mobility is total, in other words all the nodes of the network can move. We have shown that such mobility can be an asset for improving network security and avoiding some attacks. For this, we worked on the key management issue in WSNs. In this context, we proposed a new key management scheme based on random key distribution. Our solution uses sink and node mobility to improve connectivity and confidentiality in WSNs. We implemented our solution and compared it with two other reference schemes to show its effectiveness.