Improvements on acquisition of Secondary Synchronization Channel in W-CDMA

The timing relationship between base stations is asynchronous in W-CDMA system. So the three-step cell search algorithm is introduced in 3GPP protocols in order to fast identify the special base station. The second step, Secondary Synchronous Channel(S-SCH) acquisition, is much critical, but the compute complexity of the conventional matched filter banks method is very large. We propose Partial Fast Hadamard Transform(PFHT) according to the S-SCH structural property, which extremely reduces the compute complexity to almost 70%. On the other hand, a Distributed Sub-Graph Search algorithm is put forward to save more complication than RS code table brute-force search. In a word, the hardware complexity is dramatically cut down by the improvement scheme, which is valuable for engineering applications.