A Dual-Pronged Solution for Accurate Decentralized Tag Systems: RSSD-Based DoA and Tag Design

Localization systems play a crucial role in various IoT applications; however, traditional techniques require significant computational resources and complex hardware, making them impractical for resource-limited devices. This paper introduces a dual-pronged approach that addresses these challenges by focusing on reducing computational complexity, optimizing tag design, and enhancing Direction-of-Arrival (DoA) estimation accuracy in real-world scenarios. A Received Signal Strength Difference (RSSD)-based DoA method using a tilted array configuration is proposed, requiring only a single subtraction for RSSD calculation. A calibration technique mitigates anchor-tag misalignment, reducing Root-Mean-Square Error (RMSE) from 12.50 to 60. Furthermore, antenna directivity and tilting angle are analyzed, introducing RSSD slope as a metric for design-performance optimization. Experiments confirm that higher RSSD slopes improve estimation accuracy and noise robustness. These findings enable efficient localization solutions for small, power-constrained devices, paving the way for real-world IoT applications.