Hybrid RSS-RTT localization scheme for wireless networks

The hybrid localization techniques have attracted significant research interest since a variety of localization metrics can be easily obtained by most wireless devices. This paper presents a hybrid localization scheme that combines received signal strength (RSS) and round-trip time (RTT) information. It is based on a RSS ranging technique that dynamically update the model that best fit the RSS information to the actual distance. RTT information, among other heuristics, are used to refine the search of that model. Once distances have been estimated, the position of the mobile station (MS) is estimated using a trilateration technique that combines the RSS and RTT ranging estimates after applying a median filter to remove outliers. By means of simulations and measurements, this paper demonstrates that combining RSS and RTT information it is possible to outperform the conventional RSS-based and RTT-based localization schemes, without using either a tracking technique or a previous calibration stage of the environment.