A high-accuracy concurrent phase-based ranging for large-scale dense BLE network

Nowadays, Bluetooth Low Energy (BLE) radios are deployed in many smart-phones and low-cost low-power smart devices. In addition, BLE based location services are deployed in many applications such as smart-buildings and industrial automation, where a scalable high-accuracy ranging solution is required for Real-Time Location Systems (RTLS) and real-time ranging. In state-of-the-art phase-based ranging, the accurate distance between two devices is measured one-to-one for each pair separately, which is not energy and time efficient for large-scale and dense deployment. In this paper, therefore, we introduce two high-accuracy concurrent phase-based ranging solutions, named group ranging, for large-scale and dense applications to improve the energy-consumption and ranging duration. Through experiment and mathematical analysis, we show that our proposed group ranging can improve the ranging duration by a factor of around n - 1, whereby n represents the number of devices. Furthermore, in this paper, we study the effect of proposed solutions in ranging accuracy in the presence of Crystal Offset Difference (COD) and phase-noise at the two devices involved in ranging. In addition, we introduce a solution to compensate for the ranging offset due to the COD. Finally, we propose how our group ranging solutions can be combined into the BLE standard data link layer in both connection-oriented and connectionless modes of operation.