Interrogating antenna comparison for distance estimation between two BLE devices

This paper presents an exploration of three interrogating antennas for smartphone distance evaluation using access control application from the brand AKIDAIA with the Bluetooth Low Energy (BLE) standard. Extensive Received Signal Strength Indicator (RSSI) collection was conducted up to 10 meters by using each single interrogating antenna one by one to compare the robustness of the received signal against multi-path effects. This data collection allowed us to generate a dataset to predict the distance between these two BLE devices. This work aims to determine the optimal antenna configuration that allows predicting a prioritization order of smartphones based on their distance from the access controller equipped with a single interrogating antenna. The results showed that the PIFA (Planar Inverted-F Antenna) provides the greatest robustness among the three antennas described in this article, with prioritization accuracy of 91.5% in indoor environments.