Double-dwell code acquisition with differentially coherent combining in DS/CDMA systems

The use of differentially coherent combining is proposed to improve the performance of a double-dwell acquisition system. The differentially coherent combining is employed to increase the reliability of a decision in the verification stage. The mean acquisition time performance of the acquisition scheme with the proposed combining scheme is analyzed in a Rayleigh fading channel and compared with that of a conventional double-dwell acquisition scheme with noncoherent combining. It is shown that the proposed acquisition scheme outperforms the conventional one, and that the performance improvement increases as the frequency offset increases