Patent ID: 7310368

Claim:
An apparatus for initial synchronization and cell search in CDMA systems based on a multipath energy window comprises: a plurality of tap delay lines, in which the number S of the tap delay lines is determined by the minimal time required for initial synchronization and cell search, for sampling baseband signals r(t) with a rate T c /M, sending the S tap outputs from the S tap delay lines to S parallel correlators, where T c /M is a fraction sampling interval, T c is the chip rate of the CDMA system and M is the oversampling rate; each of the S parallel correlators performs channel evaluation of a single path in one integrating period NT C , clears the respective multiplying accumulation units of each correllator after sending the evaluated results to respective amplitude judging units; a plurality of amplitude judging units for judging whether the square value of the channel evaluation amplitude obtained from respective correlators is larger than a threshold which is used for judging a signal arrival path as a pure interference path when the evaluation amplitude is lower than the threshold, sending the evaluated amplitude with which the pure interference paths are replaced with a zero value to a buffer, and then providing the evaluated amplitudes to a sliding multipath energy window calculation unit one by one through a parallel-series conversion unit; a sliding multipath energy window calculation unit for calculating S outputs from sliding multipath energy windows for the S channel evaluations obtained in every integration interval; and a maximal energy window calculation unit for comparing every value output from the sliding multipath energy windows and selecting the amplitude having maximal value and the phase of the local pilot PN code which corresponds to the amplitude.