A study of TDOA estimation using Matrix Pencil algorithms and IEEE 802.11ac

The IEEE 802.11ac is an emerging WLAN standard for the 5 GHz band in which multiple input multiple output (MIMO) and wider channel bandwidths are enhanced compared to 802.11n. In this paper, we present some techniques for estimating the time difference of arrival (TDOA) associated with signals in a multipath communication channel for wireless indoor positioning. Recently, the Unitary Matrix Pencil (UMP) and the Beam-Space Matrix Pencil (BMP) algorithms have been presented to estimate the direction of arrival (DOA) of coherent or non-coherent signals using uniform linear arrays (ULA). We have applied these algorithms for TDOA estimation using OFDM systems. The accuracy, stability, and complexity of various MP algorithms are investigated using the 802.11ac standard, and compared to the corresponding performance of 802.11n. The performance of using multiple OFDM training symbols and wider channel bandwidths are emphasized. Experimental results show that accuracy and stability in the range of a few hundreds of picoseconds have been achieved.