WiFi Fingerprint Localization with Circular Boundary

For the issues (heterogeneity, heavy initial training, etc.) in WiFi fingerprinting-based positioning technology, a circular boundary is proposed in this letter. First, the correctness of the boundary is proved by theoretical derivation. Then, for the fact that only the information of reference points (RPs) is known in real environment, objective functions are set and the relationship between the center and radius is explored to solve the expression of circular boundary. Finally, the AP-Sequence algorithm is adopted to estimate users' location. Experimental results show that the proposed algorithm with low-overhead fingerprinting achieving an average localization error of 5-8 m outperforms other state-of-the-art approaches based on AP-Sequence (e.g. FreeLoc, SBL.).