Bounds on distributed TDOA-based localization of OFDM sources

One main drawback of using time difference of arrival (TDOA) methods for source localization and navigation is that they require centralization of multiple copies of a signal. This paper considers blindly estimating the location of a cyclic prefix (CP) in an orthogonal frequency division multiplexing (OFDM) signal, enabling distributed TDOA computation up to an integer ambiguity. This ambiguity can be resolved using integer least-squares methods, if enough TDOAs are available. The contributions of this paper are derivation of the Cramer-Rao lower bound (CRLB) on locating the CP, and hence on the underlying source localization problem.