The optimization of sensor relocation in wireless mobile sensor networks

Wireless Sensor Networks (WSNs) have been an active research area these years due to their broad range of potential applications. Several research issues, which include energy-aware routing, sensor deployment problems, data aggregation, etc., have been broadly discussed in this network environment. Among these researches, the most important issue is to conserve the usage of the limited battery energy of the sensor in the WSN to prolong its network lifetime for as long as possible. This paper considers a movement-assisted sensor deployment problem in a cluster-based WSN, in which the sensor devices are capable of moving. Based on this mobility assumption for sensors, the redundant sensors can relocate their positions to the low battery energy clusters to increase the overall network lifetime of the WSN. A network optimization problem called the Optimization of Movement-Assisted Deployment Problem (OMADP) is formulated. The OMADP aims to determine the optimum sensor relocation scheme such that the network lifetime value of the resulting network will be maximized. The NP-hardness result of the OMADP was also conducted. We propose a heuristic algorithm to give an approximate solution to the OMADP. The simulation results show that the proposed method performed better in prolonging the network lifetime of a WSN in practice, compared to other movement-assisted deployment algorithms. (C) 2009 Elsevier B.V. All rights reserved.