A Study of Wireless Indoor Positioning Based on Joint TDOA and DOA Estimation Using 2-D Matrix Pencil Algorithms and IEEE 802.11ac

This contribution addresses the problem of highly resolving the propagation time delays and the relative direction of arrivals (DOAs) associated with signals in multipath communication channels for wireless indoor positioning. The recent subspace based algorithms, represented by two-dimensional matrix pencil (2-D MP) algorithms, are applied in a new way to estimate these parameters simultaneously from the measured space channel frequency response (S-CFR) using multiple antennas and wideband orthogonal multicarrier signals. The performance of using spatial multiplexing and orthogonal frequency-division multiplexing (OFDM) systems for wireless positioning are presented. A non-iterative hybrid least square estimator has been presented to estimate the mobile unit (MU) coordinates based on the time difference of arrival (TDOA) and DOA estimates. The proposed estimator solves the problem of the initial guess and that of partitioning. It is a robust estimator against channel fading and low signal-to-noise ratio (SNR). Experimental results using the emerging IEEE 802.11ac standard show that accuracy in the range of 1.5 cm can be achieved for 2-D wireless indoor positioning.