MuSpel-Fi: Multipath Subspace Projection and ELM-Based Fingerprint Localization

This letter proposes a multipath subspace projection and extreme learning machine (ELM)-based indoor fingerprint localization algorithm called MuSpel-Fi, where the channel state information (CSI) is utilized as the raw data to establish fingerprints. In this algorithm, the CSI is firstly organized into a time-domain matrix and then is projected into a subspace. This processing not only preserves the channel multipath information as much as possible, but also reduces the data dimension. Based on the reduced dimension projected data, the ELM network is exploited to implement the fingerprint localization. Considering the limited performance of a single ELM network, multiple ELM networks are jointly optimized to improve the localization performance. The experimental results demonstrate that the proposed MuSpel-Fi algorithm has higher positioning accuracy than traditional ones.