Recursive delay estimation and demodulation of asynchronous DS-CDMA signals

We compare several near-far resistant recursive delay tracking algorithms and propose a robust multiuser detection scheme for asynchronous DS-CDMA systems. The delay tracking algorithms are based on the so-called `propagator method´ which permits direct update of the noise subspace from the collected data via a chosen criterion. The estimated delays are then used to demodulate the received signal using a robust formulation of the decorrelating receiver. We compare the tracking performance of the LMS, exponentially weighted RLS, exponentially weighted H^∞ and time-varying H^∞ solutions, and also compare the performance of our robust receiver with the decorrelating and MMSE receivers