The Optimized Deployment Strategy In Wireless Sensor Networks

Optimal node placement is a very challenging problem in wireless sensor networks (WSNs). The optimized deployment strategy can be helpful for various layers of the communication protocol stack. In this paper, research works studied include: 1) How to design optimization deployment strategy for balancing the energy consumption and improving the network lifetime. 2) How to optimize the path planning of the mobile beacon for the sensor network location.The benefits of a heterogeneous architectures composed of a resource rich mobile node and a large number of simple static nodes are investigated in this paper. The mobile node can either act as mobile relay or mobile sink. The strategy of minimizing traffic of bottleneck nodes is proposed to find the optimal location of the mobile resource rich node. We first consider a line network, and compute the lifetime for different deployment algorithms for four cases 1) when the resource rich node is placed close to the sink 2) when the resource rich node is placed on the middle of the line network 3) when the resource rich node is placed on the optimal place of the line network 4) when the resource rich node and sink are jointly deployed. We find that when the resource rich node and sink are jointly deployed it will result in the maximum improvement in lifetime of line network. We then investigate the performance of a circular dense network with one mobile relay, and results show the improvement in network lifetime over an all static network. The mobility and routing algorithms are jointly considered in this strategy to balance the network traffic and prolong the network lifetime. A distance-based energy efficient sensor placement (DBEEP) strategy is proposed for lifetime maximization. The relations of adjusted distance, communication range, network radius and the number of nodes are studied in this paper, on which the network can be jointly optimized to satisfy different demands. In simulations, we demonstrate that the energy consumption on DBEEP strategy is much less than that on the other strategies.Initial energy assignment (IEA) strategy is another static deployment strategy. The IEA strategy is proposed according to their energy consumption for lifetime maximization. In the two-tier sensor network architecture, the IEA strategy can be used for the second-tier of relay nodes. The location and energy level of the sensors are given to optimize the load balance and prolong the network lifetime.An efficient routing algorithm based on hop distance without location information is investigated in this study. The wave mapping coordinate (WMC) system is considered to address the localization problem, and the wave distance of WMC is optimized according to the optimal hop distance. The simulation results confirm the high routing performance of WMC systems.A double-circle localization algorithm based on a single mobile beacon aware of its position is presented in this paper. The mobile beacon rotates around two central points. The whole area will be covered two times in this strategy by the mobile beacon. And the location of every sensor can be obtained by the sine theorem. The RSSI is not used to calculate the distance of sensors and the mobile beacon; it is only used to estimate their polar angle of two coordinate systems. And the path that mobile beacon should travel along has been optimized. In this case, a fundamental research issue is the planning of the path that the mobile beacon should travel along in order to minimize the localization error as well as the time required to localize the whole network. The experimental results show that the accuracy of the localization is good for most applications.