Generally, localization is a nonlinear problem, while linearization is used to simplify this problem. Reasonable approximations could be achieved when signal-to-noise ratio (SNR) is large enough. Energy is a critical resource in wireless sensor networks, and system lifetime needs to be prolonged through the use of energy efficient strategies during system operation. In this paper, a closed-form solution for received signal strength (RSS)-based source localization in wireless sensor network (WSN) is obtained. A sensor selection method is proposed to improve the localization accuracy as well as to save energy consumption. By selecting only a limited number of sensor nodes based on the model accuracy and geometry structure analysis, localization performance is improved, and energy consumption is reduced. In addition, extensive simulations are presented to demonstrate that the estimation performance with the proposed sensor selection method is better than that without sensor selection.
In many wireless sensor network applications, it should be considered that how to trade off the inherent conflict between energy efficient communication and desired quality of service such as real-time and reliability of transportation. In this paper, a novel routing protocols named balance energy-efficient and real-time with reliable communication (BERR) for wireless sensor networks (WSNs) are proposed, which considers the joint performances of real-time, energy efficiency and reliability. In BERR, a node, which is preparing to transmit data packets to sink node, estimates the energy cost, hop count value to sink node and reliability using local information gained from neighbor nodes. BERR considers not only each sender' energy level but also that of its neighbor nodes, so that the better energy conditions a node has, the more probability it will be to be chosen as the next relay node. To enhance real-time delivery, it will choose the node with smaller hop count value to sink node as the possible relay candidate. To improve reliability, it adopts retransmission mechanism. Simulation results show that BERR has better performances in term of energy consumption, network lifetime, reliability and small transmitting delay.
This paper presents a symmetric cooperation strategy for wireless sensor networks, aiming to improve the transmission efficiency of the network. The cooperation strategy is implemented by partitioning the nodes into several cooperative groups. Then, in each group, the optimal cooperative bandwidth allocation is obtained based on Raiffa-KalaiSmorodinsky bargaining solution (RBS). Numerical results show that the symmetric cooperation strategy can improve the sensor node's transmission efficiency dramatically.
在LMAP(Localization with mobile anchor points in wireless sensor networks)算法的基础上提出了一种改进算法:ELMAP算法。ELMAP算法改进了原算法的参考信息分组的选取机制,以达到摆脱对节点传输模型假设的依赖和提高实际应用中定位性能的目的。该算法选取具有相同接收信号强度(RSS)值的信息分组作为参考信息分组来对未知节点进行定位计算。仿真结果表明ELMAP算法比原算法具有更强的环境适应能力,并且可以通过调节接收到的信息分组数量和限定用于定位计算的参考信息分组的RSS值的范围来达到最佳状态。
This paper presents a symmetric cooperation strategy for cooperative relay networks with multiple users. The multi-user symmetric cooperation model and the relay selection algorithm are proposed. Then, the time slot allocation problem is cast into a bargaining problem, and the optimal time slot allocation solution is obtained by Nash bargaining solution (NBS). Moreover, we also consider the implementations of the cooperation strategy, i.e., the grouping and admission control algorithm. Simulation results show that users can obtain larger rates under the symmetric cooperation strategy than the non-cooperative case.
