| The coarse acquisition performance of a direct-sequence spread-spectrum receiver utilizing narrowband interference suppression techniques is established. Both single and multiple user systems are considered, the latter in the context of a CDMA overlay scenario. In the single user system, the performance is given when either a transform domain processing filter, a linear prediction filter, or a two-sided Wiener filter is employed. Both sinusoidal interference and narrowband Gaussian interference with constant spectral density are considered. When the linear prediction filter is used, it is shown that despreading with a version of the spreading code which has been distorted by the interference rejection filter appreciably enhances the performance. Results are presented for both a parallel acquisition strategy and a serial strategy; also, both long and short spreading sequences are considered. Among other things, we show that while the parallel structure operates faster, the serial structure provides much more uniform performance for either short or long period sequences. Finally, the coarse acquisition performance of a CDMA overlay system is considered, and it is shown that the presence of a narrowband interference rejection filter significantly improves the performance. |
