Blind User Detection and Delay Acquisition in Doubly-Dispersive DS/CDMA Fading Channels

The problems of detecting the presence of a new user and of estimating the delays of its multipath replicas in a direct-sequence/code-division-multiple-access (DS/CDMA) system are investigated. Despite previous works, we consider a doubly-dispersive fading channel model and we propose a new code-aided detection algorithm which relies on the application of a powerful statistical tool known as the method of sieves. The proposed detector is blind and bounded constant false alarm rate. As a byproduct of the detection stage, a new blind procedure to estimate the multipath channel delays of the detected user is also derived.