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.