Distributed RSSI-sharing for two-way ranging base station selection

While Two-Way Ranging (TWR) is generating interest as a accurate and low-cost indoor localization technique, most TWR research focuses primarily on algorithms or error reduction, with little regard to a fundamental system-level issue: deciding which Base Stations (BS) should perform the TWR. While most researchers acknowledge the need for a scanning phase to select BSs before the ranging phase is carried out, this scanning phase has not been explored in detail. In that regard, we utilize Received Signal Strength Indicator (RSSI) as the basis for BS selection. RSSI is a measure of the signal strength of an incoming radio packet, and is found on virtually every Radio Frequency (RF) transceiver, making its use almost free of additional hardware cost. While RSSI measurements are unreliable in indoor environments and cannot be practically used for localization, we show that RSSI is a reliable indicator for the scanning phase and BS selection. More specifically, we develop a Distributed RSSI-Sharing technique to efficiently select BSs and create a simulation to test this technique. We implement and test technique on actual hardware with good results and finally propose RSSI-smoothing and a BS-Reduction method to improve the performance.