A non-coherent tracking scheme for the RAKE receiver that can cope with unresolvable multipath

A novel non-coherent tracking technique for the RAKE receiver is introduced that has a good tracking performance even if multipaths cannot be resolved. Multiple chip-spaced correlators are used on unresolvable multipaths to provide estimates with uncorrelated noise. It is shown that the proposed tracker finds the pseudonoise code timing that maximizes the output of the maximal ratio combiner. The new tracking technique is easy to implement and does not require significantly more computations than conventional non-coherent time tracking techniques. The superior performance of the new tracking loop over conventional early-late time estimators in frequency-selective fading channels is demonstrated by means of computer simulations.