Cooperative TDOA estimation with trigger relay

In this paper, we investigate the relaying issue of Zero-Padding (ZP) Orthogonal Frequency Division Multiplexing (OFDM) technique to estimate Time Difference of Arrival (TDOA) for locationing applications. In order to benefit from the easy processing of Amplify-and-Forward (AF) relay as well as the noise and interference cancellation of Decode-and-Forward (DF) relay schemes, we introduce the trigger relay technique for TDOA estimation. The trigger relay possesses the merit of bandwidth efficiency, since only a short pilot or preamble needs to be sent. Compared to its counterparts AF and DF relays, trigger relay achieves a better performance in terms of system complexity and TDOA accuracy. Gaining from multipath diversity, the trigger relay TDOA resolution can be improved further.