Blind code timing and carrier offset estimation for DS-CDMA systems

We consider the problem of joint carrier offset and code timing estimation for CDMA (code division multiple access) systems. In contrast to most existing schemes which require a multi-dimensional search over the parameter space, we propose a blind estimator that solves the joint estimation problem algebraically. By exploiting the noise subspace of the covariance matrix of the received data, the multiuser estimation is decoupled into parallel estimations of individual users, which makes computations efficient. The proposed estimator is non-iterative and near-far resistant. It can deal with frequency-selective and time-varying channels. The performance of the proposed scheme is illustrated by some computer simulations.