Patent ID: 8873605

Claim:
A scrambling code estimation method used on an uplink of a terminal in a Wideband Code Division Multiple Access (WCDMA) system, a signal transmitted by the terminal on said uplink being transmitted in frames and scrambled with a scrambling code, the scrambling code being constructed from a Gold sequence (z n ) obtained as sum of a first (x n ) and of a second (y) sequences of maximal length, said method comprising: sampling samples, at the chip frequency of the scrambling code, the signal received by a receiver; performing a differential processing of the samples, said differential processing comprising a Hermitian product of successive samples and a calculation of an imaginary part of said Hermitian product, the differential treatment supplying a sequence of differential values (v(k)); multiplying the sequence of differential values by a decimated and shifted version of the second sequence ({tilde over (Y)}), known from the receiver, to obtain a sequence of observables (ε(k)); performing an iterative decoding of the sequence of observables to obtain a shifted and decimated version of the first sequence ({tilde over (x)} n ); and determining, at a given instant, the content (SR x ) of a shift register of a generator of the first sequence, and one deduces therefrom the scrambling code.