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In this paper, we present a blind and robust algorithm to jointly estimate the directions of arrival (DOAs) and propagation delays in DS/CDMA systems. The rationale of the proposed approach is a hybrid of one-dimensional (1-D) multiple signal classification (MUSIC) algorithms and constrained spatial/temporal filtering processes. As previously addressed TST MUSIC, two temporal (T)-MUSIC and one spatial (S)-MUSIC are employed alternatively in the proposed algorithm to estimate the group delays and the DOAs respectively. However, by utilizing the structure of the data model, no training sequences are required. Furthermore, a constrained temporal filtering process and a constrained spatial beamforming process, which minimize the filtered noise power under a set of judiciously chosen linear constraints, are now employed after the T-MUSIC and S-MUSIC respectively. These filtering processes aim to effectively partition the incoming rays and to be robust against the propagation errors in the tree-structured estimation scheme so that the overall performance can be enhanced. Also, the incoming rays are grouped, isolated and estimated, and the pairing of the estimated delays and DOAs is automatically achieved without extra computational overhead. Furnished simulations show that the new approach can exhibit satisfactory performance with low complexity compared with previous works.

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