Sensor networks are a sensing, computing and communication infrastructure that are able to observe and respond to phenomena in the natural environment and in our physical and cyber infrastructure. The sensors themselves can range from small passive micro-sensors to larger scale, controllable weather-sensing platforms. To reduce the consumed energy of a large scale sensor network, we consider a mobile sink node in the observing area. In this work, we investigate how the sensor network performs in the case when the sink node moves. We compare the simulation results for two cases: when the sink node is mobile and stationary considering lattice and random topologies using AODV protocol. The simulation results have shown that for the case of mobile sink, the consumed energy is better than the stationary sink (about half of stationary sink in lattice topology). Also for mobile sink, the consumed energy of lattice topology is better than random topology.
Vehicular Ad-hoc Networks (VANETs) are an instance of Ad-hoc networks, which are general-purpose distributed wireless networks interconnected without the need of any centralized infrastructure. VANETs are expected to be massively deployed in upcoming vehicles, because their use can improve the safety of driving and makes new forms of inter-vehicle communications possible as well. The simulation of VANETs requires two different components: a vehicular traffic simulator, capable to provide an accurate mobility model for the nodes of a VANET, and a network simulator, for simulating the behavior of a wireless network. In this paper, we provide a survey of mobility models proposed for VANETs. We analyze challenges and future perspectives of VANET simulators and current routing solutions for VANET.
Wireless mobile networks and devices are becoming increasingly popular to provide users the access anytime and anywhere. We are witnessing now an unprecedented demand for wireless networks to support both data and real-time multimedia traffic. The wireless mobile systems are based on cellular approach and the area is covered by cells that overlap each other. In mobile cellular systems the handover is a very important process. Many handover algorithms are proposed in the literature. However, to make a better handover and keep the QoS in wireless networks is very difficult task. For this reason, new intelligent algorithms should be implemented to deal with this problem. In this paper, we carried out a comparison study of two handover systems based on fuzzy logic. We implement two Fuzzy-Based Handover Systems (FBHS) called FBHS1 and FBHS2. The performance evaluation via simulations shows that FBHS2 has better behavior than FBHS1 and can avoid ping-pong effect in all simulation cases.
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