Design and Evaluation of a BLE-Based Beamforming Measurement System for RSSI Differentiation

This paper presents the design and evaluation of a Bluetooth Low Energy (BLE)-based beamforming measurement system for enhanced terminal differentiation in indoor environments. The conventional sum-beam method using array antennas often fails to provide sufficient Received Signal Strength Indicator (RSSI) contrast between adjacent Smart Blocks, limiting the precision of proximity sensing. To overcome this, we propose a novel beamforming technique that employs microcontroller-driven RF switching to compare the sum and delta beams. This hardware-implemented approach ensures that the received power at the terminal is determined exclusively by the antenna radiation pattern, thereby improving spatial selectivity. Experimental measurements conducted on a Gate-Free fare system testbed demonstrate that the proposed method achieves up to 9.3 dB improvement in RSSI separation compared to conventional configurations. The system’s measurement repeatability and robustness were validated through repeated trials under varying distances and terminal heights. The results confirm the feasibility of deploying the proposed system in BLE-based real-time localization and sensing applications requiring high differentiation accuracy.