Research Of Deployment In Underwater Wireless Sensor Networks

With the rapid development of industry technology and growing requirement of energy, the exploitation of ocean resource has become a focus by relative countries. The UWSN has attracted the attention of governments, research institutions and companies because of its broad future application in the fields of military battle, ocean data acquisition, pollution prediction, ocean exploiting, sea-disaster avoiding and sea-state monitoring. These factors have gradually brought the low-cost and reliable UWSN to a new hot research topic.Deployment of the sensors is the basic issue of UWSN. The way of deployment is the foundation of the coverage management. It influences the building cost, coverage quality, topological structure and routing algorithm of the network. From the aspect of raising energy efficiency, this paper discusses several problems including the minimum sensors coverage set, the density-decreasing sensors deployment, and the high efficiency mobile deployment. The main work is as follows:(1) The problem of the minimum sensors coverage setThe sensors in UWSN are broadly deployed in the target area. They can surely cover the whole area when they're all working. But the multiple coverage in some places cause a great waste of energy. According to the situation, the problem of the minimum node coverage set is raised in this paper, in order to find a minimum coverage set that satisfies the requirement of coverage rate and number of sensors.(2)The density-decreasing deployment against the energy holeEnergy equalization is an important issue in UWSN. It's a basic to the analyzing and solving of coverage management. For this issue, based on the data acquisition characteristic of the networks, the density-decreasing deployment that can improve energy efficiency and eliminate the rest energy is given in this thesis. The deployment reduces the density of deployed nodes, decreases the hardware cost and rest energy to construct the network, and raises the efficiency of energy.(3)The high efficiency mobile deployment strategySuppose that the free-distributed sensor nodes are movable in area coverage, the ideal distribution of sensors with maximum coverage rate is deduced. Furthermore, the high efficiency virtual force algorithm FVFA - an improved algorithm of VFA - is raised, considering the factors of useless movement, boundary effect, and optimal moving distance and so on. The simulation suggests the FVFA is a simplified self-recognized algorithm, which can efficiently increase the coverage rate and coverage efficient of the small-scale UWSN.In summary, this dissertation gives the solution to the problem of high energy efficiency node deployment. It has significant theoretical and practical value to improving the research and application of UWSN.