Corona: Positioning Adjacent Device with Asymmetric Bluetooth Low Energy RSSI Distributions

We introduce Corona, a novel spatial sensing technique that implicitly locates adjacent mobile devices in the same plane by examining asymmetric Bluetooth Low Energy RSSI distributions. The underlying phenomenon is that the off-center BLE antenna and asymmetric radio frequency topology create a characteristic Bluetooth RSSI distribution around the device. By comparing the real-time RSSI readings against a RSSI distribution model, each device can derive the relative position of the other adjacent device. Our experiments using an iPhone and iPad Mini show that Corona yields position estimation at 50% accuracy within a 2cm range, or 85% for the best two candidates. We developed an application to combine Corona with accelerometer readings to mitigate ambiguity and enable cross-device interactions on adjacent devices.