WiFi Realtime Localization for Smartphones by MIMO-OFDM Tracking Algorithm

Abstract

This paper investigates the localization problem based on superimposed signals in multipath environments. First, we estimate the multipath parameters embedded in MIMO-OFDM signals via the space-alternating generalized expectation-maximization (SAGE) algorithm. Then to mitigate the disadvantages of initial value dependency and clutter problem of SAGE, we resort to the joint probabilistic data association (JPDA) method. Considering the computational burden, we adopt a modified JPDA technique, which is computationally tractable in applications with high clutter density. Hence it comes naturally an integrated localization algorithm, simulations validate its efficiency. Finally, we implement an accurate WiFi realtime localization system on smartphones that can be deployed on commodity WiFi infrastructure, which demonstrates the superiority of the proposed method.