Date Added: Apr 2013
In the authors' papers before, two three-dimensional localization schemes which are called Iterative Calculation of Secondary Grid Division localization scheme (ICSGD) and a range free Three Dimensional Optimum Space Step Distance Localization scheme (3D-OSSDL) are proposed respectively. In ICSGDLS scheme, forty beacon nodes and five hundred unknown sensor nodes were randomly deployed in a cube, which is divided into smaller cubes twice. The position information of unknown nodes could be got by iteratively calculating the centroid of smaller cubes. However, in 3D-OSSDL algorithm all nodes are randomly deployed in space and forms arbitrary network parameters. By optimizing distances from the network model, the optimum space step distance from nodes to anchors is obtained and the coordinates of all unknown nodes are derived finally.