The invention relates to a method and apparatus for acquiring a complex spreading code of a direct sequence spread spectrum signal (DSSS) by acquiring a state of a spreading code generator capable of generating the complex spreading code. A sequence of bipolar differential product values, which sign is independent on data transmitted by the DSSS signal, is obtained by combining in-phase and quadrature samples of the DSSS signal for adjacent chip intervals. This sequence is provided to a linear block decoder for obtaining a codeword of a linear block code, which is defined by a structure of the spreading generator and the differential product operation. The codeword is used to compute the state of the spreading code generator.