Sub-nanosecond accuracy of TDOA estimation using Matrix Pencil algorithms and IEEE 802.11

This paper presents some techniques for estimating the time difference of arrival (TDOA) associated with signals in a multipath communication channel for wireless indoor positioning. Recently, variants of Matrix Pencil (MP) algorithms have been presented to estimate the direction of arrival (DOA) of coherent or non-coherent signals using uniform linear arrays (ULA). These include the Unitary Matrix Pencil (UMP), the Single Invariance, and the Multiple Invariance Beam-space Matrix Pencil (BMP) algorithms. We have applied these algorithms for TDOA estimation using OFDM systems. The accuracy, stability, and complexity of various MP algorithms are investigated using IEEE 802.11a and IEEE 802.11n system parameters. Experimental results show that accuracy and stability in the range of a few hundreds of picoseconds are achieved using one OFDM training symbol and 20 MHz bandwidth.