Data-Aided Location Estimation in Cellular OFDM Communications Systems

In this paper, location estimation algorithms for cellular communications systems employing orthogonal frequency division multiplexing (OFDM) are investigated. To determine the location of a mobile station, usually time difference of arrival (TDOA) measurements are performed with at least three base stations using pilot symbols included in the signal streams. With these TDOAs then the location is estimated. However, the timing estimation process is faced by different effects that restrict the performance. For instance, limited number of pilot symbols, inter-cell interference, and multipath propagation decrease the accuracy of the timing estimates, and hence, position estimates. Therefore, we propose to feed back decided data symbols where particularly data-aided timing estimation and interference cancellation are considered in the location estimation context. Simulation results for a 3GPP-LTE system show the ability of these algorithms to increase the overall accuracy and reliability of location estimates.