Joint Twin-Cell Detection for Spread Spectrum Code Acquisition in the Presence of Fractional Doppler Frequency Offset

In this paper, a novel detection method called the twin-cell detection is addressed for spread spectrum code acquisition in the presence of fractional Doppler frequency offset (FDFO). When the FDFO exists, the correlation peak used for detection during the acquisition process is split into two smaller neighboring peaks, resulting in severe degradation in the detection performance (and, consequently, in the overall acquisition performance). In the twin-cell detection, a decision variable for detection is formed by combining two consecutive correlator outputs, so that the reduction in the correlation value due to the FDFO can be alleviated. The simulation results show that the proposed scheme can offer better acquisition performance over the conventional scheme based on the cell-bycell detection.