Localization in wireless sensor networks using directionally information

Localization in sensor networks can be defined as “identification of sensor node's position”. For any wireless sensor network, the accuracy of its localization approach is highly aimed. Here we explore the possibility of using free-space-optical (a.k.a. optical wireless) communications to solve the 3-D localization problem in ad-hoc networking environments. There are two methods to solve localization problem, Range based & Range Free. In Range-based methods require a higher node density or costly devices such as sonar. In our proposed approach we use direction related information provided by a physical layer using optical wireless, requiring a very low node density (2-connectedness) and no ranging technique. We analyze the accuracy of localization with respect to varying node designs (e.g., increased number of transceivers with better direction related information) and density of GPS-enabled and ordinary nodes as well as messaging overhead per re-localization. This method still works well with sparse networks with little message overhead and small number of anchor nodes as little as 2.