Distance Estimation Using Low Calibrated Tx in BLE’S Advertising Mode for COVID-19 Contact Tracing

The ability to estimate distance between people has been an important aspect in contact tracing especially in this Covid-19 pandemic. This is because, distance is one of the crucial element in determining whether a person is a close contact or not. In this context, Centers for Disease Control (CDC) and Prevention has provided a guideline to be followed, which is the distance of no more than 6-feet (~2 m) to be accepted as close contact. With regards to that, many of the solutions in existence are adopting Received Signal Strength Indicator (RSSI) in Bluetooth Low Energy’s (BLE) connected mode to determine distance. However, the mainstream approach has two main setbacks and they are: (1) Unreliable real-life implementations and (2) Ability to cater for limited number of users which makes it unscalable. Thus, in providing some closure, our study proposed using low calibrated Transmission Power, Tx, in BLE advertising mode for indoor scene, to effectively conduct distance estimation for the pandemic. Results obtained have shown that our proposed solution has a maximum error of 0.3209m in distance estimation within the distance of 2 m. Contributions of this study is two-fold: (1) It provides a novel approach in estimating distance using BLE’s RSSI in the advertising mode utilising low calibrated Tx and (2) The proposed solution eliminates limited number of users that makes it scalable.