Convergence Time Analysis of Self-stabilizing Algorithms in Wireless Sensor Networks with Unreliable Links

In wireless sensor networks, too many or too few power-on sensors may cause the waste of resources or poor sensing efficiency; thus, controlling the number of active sensors to meet the predicted target number is the purpose of this research. However, the total number of sensors may be unstable because of the increment and damage to the sensors. It is difficult to control the number of active sensors to meet the predicted target in this condition. Previous studies proposed the Gur Game algorithm to solve this problem. However, the convergence time of the Gur Game algorithm is too long, which causes sensors to consume excessive power and waste resources. Therefore, this paper proposed the QoS Control with Quick Convergence (QC2). This method utilizes total virtual value to accelerate the convergence operation from the number of sensors to the target number. The experiment result shows that the QC2 method can cause the number of sensors to converge rapidly with the target value and that QC2 can be over a hundred times faster than the Gur Game algorithm with regard to convergence.

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GPS-Free Localization Algorithm for Wireless Sensor Networks

Sensors ◽

10.3390/s100605899 ◽

2010 ◽

Vol 10 (6) ◽

pp. 5899-5926 ◽

Cited By ~ 25

Author(s):

Lei Wang ◽

Qingzheng Xu

Keyword(s):

Wireless Sensor Networks ◽

Sensor Networks ◽

Coordinate System ◽

Probability Model ◽

Local Coordinate System ◽

Convergence Time ◽

Wireless Sensor ◽

Global Coordinate System ◽

Multiplication Factor ◽

Localization Scheme

Localization is one of the most fundamental problems in wireless sensor networks, since the locations of the sensor nodes are critical to both network operations and most application level tasks. A GPS-free localization scheme for wireless sensor networks is presented in this paper. First, we develop a standardized clustering-based approach for the local coordinate system formation wherein a multiplication factor is introduced to regulate the number of master and slave nodes and the degree of connectivity among master nodes. Second, using homogeneous coordinates, we derive a transformation matrix between two Cartesian coordinate systems to efficiently merge them into a global coordinate system and effectively overcome the flip ambiguity problem. The algorithm operates asynchronously without a centralized controller; and does not require that the location of the sensors be known a priori. A set of parameter-setting guidelines for the proposed algorithm is derived based on a probability model and the energy requirements are also investigated. A simulation analysis on a specific numerical example is conducted to validate the mathematical analytical results. We also compare the performance of the proposed algorithm under a variety multiplication factor, node density and node communication radius scenario. Experiments show that our algorithm outperforms existing mechanisms in terms of accuracy and convergence time.

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