Single-user sparse channel acquisition in multiuser DS-CDMA systems
نویسندگان
چکیده
Single user channel estimation for the case of sparse channels with large delay spreads is addressed. In addition, practical pulse shapes are considered. In sparse channels, the eecient way to estimate the parameters is to estimate the continuous delays of each path, instead of using the typical discrete tapped delay line model. Due to the facts that the desired delays are not drawn from a simple nite set and that bandlimited pulse shapes are employed, the resulting methods require numerical optimization techniques. To facilitate estimation, it is proposed to optimize the spreading code employed during the training, or estimation, phase. The optimal single path spreading code is derived and extended for estimation in the multipath scenario. Both single path and multipath channel estimation are considered. The proposed algorithms are evaluated through simulation and via the determination of the Cram er-Rao lower bound on the estimation variance. Analytical approximations of key performance measures are also derived and are seen to be tight for a variety of scenarios.
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عنوان ژورنال:
- IEEE Trans. Communications
دوره 51 شماره
صفحات -
تاریخ انتشار 2003