The involvement of wireless sensor networks in large-scale real-time applications is exponentially growing. These applications can range from hazardous area supervision to military applications. In such critical contexts, the simultaneous improvement of the quality of service and the network lifetime represents a big challenge. To meet these requirements, using multiple mobile sinks can be a key solution to accommodate the variations that may affect the network. Recent studies were based on predefined mobility models for sinks and relied on multi-hop routing techniques. Besides, most of these studies focused only on improving energy consumption without considering QoS metrics. In this paper, multiple mobile sinks with random mobile models are used to establish a tradeoff between power consumption and the quality of service. The simulation results show that using hierarchical data routing with random mobile sinks represents an efficient method to balance the distribution of the energy levels of nodes and to reduce the overall power consumption. Moreover, it is proven that the proposed routing methods allow for minimizing the latency of the transmitted data, increasing the reliability, and improving the throughput of the received data compared to recent works, which are based on predefined trajectories of mobile sinks and multi-hop architectures.

Wireless Sensors Networks (WSN) is an emergent technology which aims at offering innovating capacities. Their use is increasing in many fields such as sciences, logistics, military and medically. Despite this increasing attention, WSNs have a limitation to be considered which the energy consumption that can influence the lifetime of a network. Therefore, this study aims to overcome this limitation. In this context, two new protocols namely LEACH-EA and LEACH-EC are proposed to enhance the energy consumption resulting in a longer lifetime of a network. The proposed protocols are then evaluated in both homogeneous and heterogeneous environments and compared to other protocols, namely Low Energy Adaptive Clustering Hierarchy (LEACH), Threshold sensitive Energy Efficient Sensor Network protocol (TEEN) and A Stable Election Protocol (SEP). The obtained results highlighted that our two protocols are much better then these protocols in the matter of energy consumption and stability.

Wireless Sensor Network (WSN) is a network with limited power sensing devices with a communications infrastructure, which cooperatively monitor physical or environmental conditions. The main concern of WSN is the energy consumption especially during routing of collected data to sink. In this context, the use of mobile sink and the use of cluster based routing protocols have shown considerable conservation of energy. In this paper, we have simulated three sink mobility models namely Random Walk (RW), Random Waypoint (RWP) and Gauss Markov (GM), with LEACH routing protocol for energy consumption, throughput, reliability and packet latency time with reference to number of nodes and packet rate to determinate the best configurations that offer the most suitable tradeoff between energy conservation and QoS metrics. Simulations results shows that up to node density of 0.08 node/m ² (800 nodes in 100m × 100m) with a packet rate of 1 packet/s we can obtain reasonable and acceptable values that realizes a tradeoff between the metrics that we studied in this work, or for packet rate of 4 packets/s for each sensor node with node density of 0.01 node/m ² . Beyond these last values of node density and packet rate, the network consumes more energy and the other metrics of QoS sharply decreases.

Wireless Sensor Network (WSN) is a network with limited power sensing devices with a communications infrastructure for monitoring physical or environmental conditions. The main concern of WSN is the energy consumption especially during routing of collected data to sink. In this context, cluster based routing protocols have shown considerable conservation of energy by reducing the number of transmitter nodes. On the other hand, the optimal deployment of the sink in the controlled field can also conserve network energy by reducing distances between the emitting nodes and the sink. However, deploy a sink in the middle of the controlled field is almost impossible for WSN applications such as battlefield control, the control of seismic, volcanic and toxic zone. Several works have shown that the use of a mobile sink can save this situation, by providing energy conservation similar to a sink centered in the field. However, these works did not focus on the impact of sink mobility on quality of service metrics, which is of considerable importance especially for real-time applications. In this paper, we will study the impact of sink mobility on energy consumption and QoS metrics in WSN with hierarchical routing protocols under various scenarios. Simulation results have shown that sink mobility improves energy consumption, throughput, reliability and packets latency, compared to a sink located outside the field, and may even give better results than a centered sink. Nevertheless, with high node densities and high packet rate, latency and reliability abruptly degrade.