TY - JOUR
T1 - Joint estimation of carrier offset and code timing for DS-CDMA with performance analysis
AU - Amleh, Khaled
AU - Li, Hongbin
PY - 2005/9
Y1 - 2005/9
N2 - This paper considers the problem of joint carrier offset and code timing estimation for code-division multiple-access (CDMA) systems. In contrast to existing schemes that require nonlinear iterative searches over the multidimensional parameter space, this paper proposes a blind estimator that provides an algebraic solution to the joint parameter estimation problem. By exploiting the subspace structure of the observed signal, the multiuser estimation is first decoupled into a series of single-user estimation problems, and then analytical tools of polynomial matrices are invoked for joint carrier and code timing estimation of a single user. The proposed estimator is near-far resistant. It can deal with frequency-selective and time-varying channels. The performance of the proposed scheme is examined analytically by a first-order perturbation analysis. The authors also derive an unconditional Cramér-Rao bound (CRB) that is conditioned neither on fading coefficients nor information symbols; as such, the CRB is considered a suitable lower bound for blind methods. Numerical examples are presented to evaluate and compare the proposed and a multidimensional search (MD-search)-based scheme.
AB - This paper considers the problem of joint carrier offset and code timing estimation for code-division multiple-access (CDMA) systems. In contrast to existing schemes that require nonlinear iterative searches over the multidimensional parameter space, this paper proposes a blind estimator that provides an algebraic solution to the joint parameter estimation problem. By exploiting the subspace structure of the observed signal, the multiuser estimation is first decoupled into a series of single-user estimation problems, and then analytical tools of polynomial matrices are invoked for joint carrier and code timing estimation of a single user. The proposed estimator is near-far resistant. It can deal with frequency-selective and time-varying channels. The performance of the proposed scheme is examined analytically by a first-order perturbation analysis. The authors also derive an unconditional Cramér-Rao bound (CRB) that is conditioned neither on fading coefficients nor information symbols; as such, the CRB is considered a suitable lower bound for blind methods. Numerical examples are presented to evaluate and compare the proposed and a multidimensional search (MD-search)-based scheme.
KW - Carrier offset and code timing estimation
KW - Code-division multiple access (CDMA)
KW - Cramér-Rao bound
KW - Perturbation analysis
KW - Time-selective and frequency-selective channels
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U2 - 10.1109/TWC.2005.853819
DO - 10.1109/TWC.2005.853819
M3 - Article
AN - SCOPUS:28444469468
SN - 1536-1276
VL - 4
SP - 1980
EP - 1987
JO - IEEE Transactions on Wireless Communications
JF - IEEE Transactions on Wireless Communications
IS - 5
ER -