Time delay estimation for multipath CDMA-systems based on a fast minimization technique for subspace fitting

A low complexity algorithm for parameter estimation in a block fading multipath DS-CDMA system is presented. The main contribution is a novel technique for minimizing a subspace fitting criterion which is obtained as a large sample approximation of the maximum likelihood (ML) estimator. The minimization procedure is based on an approximation of the exact criterion function, allowing a direct analytic solution. For the acquisition phase, an initialization procedure similar to alternating projections is employed which exhibits remarkable global convergence properties. The efficacy of the proposed method is demonstrated by means of numerical simulations