Beacon Deployment for Unambiguous Positioning

Instant and precise localization of a mobile user is fundamental for supporting various sophisticated indoor location-aware services. This paper focuses on achieving unambiguous user positioning using practical Bluetooth low energy (BLE) beacons with multiple discrete power levels. By receiving the beacon coverage status from a user's device, the cloud server can unambiguously pinpoint the user's location and react correspondingly. We first define the problem of beacon deployment for positioning (BDP) and provide several theoretic bounds on the number of required beacons to gain sufficient understanding on its performance behavior. The BDP problem is further formulated into an integer linear program (ILP) and solved in extensive case studies. We claim that this is the first systematic and in-depth research on beacon deployment for unambiguous user positioning. Our analysis and experiments show that the proposed solution takes O(√N) to O(N/2) beacons for N test positions, which is 2-8 times less beacons compared to that by the naive approach, while the analytical bounds are tight with the ILP results with 20% of gap.