Joint estimation of DOA and TOA for MB-OFDM UWB signals based on frequency-domain processing

This study proposes a new joint direction of arrival (DOA) and time of arrival (TOA) estimation (JDTE) scheme for multi-band orthogonal frequency-division multiplexing (MB-OFDM) ultra-wideband systems with a two-antenna receiver based on frequency-domain processing. Prior joint TOA and DOA estimation (JTDE) schemes first measure the TOAs from the received waveforms at all antennas and then obtain the DOA from the TOA measurements. The proposed JDTE method estimates parameters directly from the waveforms received at all antennas, where the channel frequency response associated with the two antenna elements can be considered as a 2D (frequency and space) 'virtual array'. The DOA is estimated by exploiting the spatial dimension of the virtual array first, and then the TOA is estimated by exploiting the frequency dimension of the virtual array. The use of the virtual array enables the number of resolvable paths to exceed the number of antennas. More importantly, the Cramer-Rao bound (CRB) of DOA estimation that is derived from the received waveforms is significantly lower than that obtained from the TOA metric, and the CRB of the estimated TOA is also slightly lower than that obtained using the JTDE scheme. Numerical simulations verify the superiority of the proposed method.