On Improving APIT Algorithm for Better Localization in WSN

Because of dynamic nature of WSN topology, localization of sensors is a significant challenge. Localization algorithms could be range-based or range-free. The approximate point in triangle (APIT) is a range-free approach. The main idea of APIT is to consider overlapping triangles. Localization with APIT algorithm leads to PIT test problem and the issue of time. We propose modification of the APIT algorithm and refer as modified-APIT. Selecting suitable triangles with appropriate distance between anchors can reduce PIT test errors (edge effect and non-uniform placement of neighbours) in APIT algorithm. To reduce the computational load and avoid useless anchors selection, we propose to segment the application area to four non-overlapping and four overlapping sub-regions. For accuracy of localization and reduction of computation time, every sub-region should contain minimum 5 anchors. The modified-APIT has better performance for different sizes of network for both grid and random deployments in terms of average error and time requirement. Variations of the size of a network and radio communication radius of anchors affect the value of average error and time requirement. To have more accurate location estimation, 5 to 10 anchors per sub-region are effective in modified-APIT

کلیدواژه ها:

Wireless Sensor Network ، Localization ، APIT ، Anchor ، Coverage