Single-channel versus multi-channel scanning in device-free indoor radio localization

Indoor localization systems that involve Wireless Sensor Networks (WSNs) identify the target position by mea- suring the Received Signal Strength (RSS), the Time of Arrival (ToA), the Time Difference of Arrival (TDoA) or the Angle of Arrival (AoA). Of these, the most promising for low-cost applications are those based on RSS measures, which exploit approximate path loss models, or more reliably the relationship between the multi-path interference (shadowing) and the target position. These methods can work with WSNs based on Wi-Fi, Bluetooth and ZigBee wireless technologies. In this paper we concentrate on device-free RSS-based indoor localization methods. These methods, which have generated much research interest in the last few years, are now starting to hit the market. Specifically, the purpose of this paper is to assess the perfor- mance improvements of a Variance-based Radio Tomographic Imaging technique, when scanning various radio channels with respect to using only one, the latter being the "minimum introduced interference" option. In our setup, the data used for target localization are captured by wireless sensors deployed in the localization area, which are in line of sight among them. The localization error metrics include the mean square error and percentiles of the error distribution.