Detection algorithms based on chip-level processing for DS/CDMA code acquisition in fast fading channels

In this paper, we propose various novel detection algorithms based on chip-level processing for direct sequence code-division multiple access (DS/CDMA) pseudo noise (PN) code acquisition in fast fading channels, wherein the fading process changes rapidly within the accumulation interval of the correlation samples between the locally generated and received PN codes. By applying the maximum-likelihood (ML) and locally optimal (LO) detection criteria to the correlation samples obtained on a chip-by-chip basis, both optimal and LO detection algorithms are derived. Both of these algorithms are found to include the conventional algorithm as a special case. Simpler suboptimal algorithms are also derived. Finally, numerical results show that the proposed algorithms can offer a substantial improvement over the conventional algorithm in fast fading channels.