Array-based time-delay estimators for multipath wideband CDMA

A robust code acquisition detector is developed based on the maximization of the output signal-to-interference plus noise ratio (SINR) for asynchronous Wideband CDMA (W-CDMA) systems with a multiple-antenna array. By exploiting an efficient low-rank multistage Wiener filter (MWF) of Goldstein and Reed, the proposed synchronization detector can be implemented practically to realistic environments. This multistage technique results in the synchronizing detection criterion that requires no inversion or eigendecomposition of a covariance matrix. As a consequence this receiver achieves a complexity that is only a linear function of the size of antenna array (J), the rank of the MWF (M), the system processing gain (N), and the number of samples in a chip interval (Q) per time step, i.e., O(JMNQ). The complexity of the equivalent detector utilized the principal signal/noise sub space-separation scheme of a data eigendecomposition. or the minimum mean-squared error (MMSE) criterion is a function of O((JNQ)(3)) per time step. Simulations are conducted to evaluate the acquisition performance of the proposed detector with a different amount of sample support and a various rank of the MWF. The performance advantage of the proposed detector over other W-CDMA timing acquisition schemes is investigated.