Frequency-Based Decoupling and Modeling of BLE RSS Measurements for Indoor Positioning

Received Signal Strength (RSS) measurements are extensively used in smartphone-based positioning applications, with Bluetooth Low Energy (BLE) and Wi-Fi being the most commonly employed wireless technologies. BLE has gained increased attention in recent years, but most commercial BLE antennas cannot identify the specific frequency of each RSS measurement due to hardware limitations. This work proposes a novel path-loss model that considers the specific frequencies within the 2.4 GHz BLE band, enabling more accurate signal propagation characterization and improved positioning performance. The model was validated using specialized software with channel-specific RSS measurements and distance estimation tests on off-the-shelf smartphones, showing a 10% increase in positioning accuracy compared to methods using the aggregate RSS distribution.