Acquisition using differentially encoded Barker sequence in DS/SS packet radio

Code division multiple access (CDMA) has drawn great attention as a candidate for future packet radio systems because of its various advantages such as high capacity or multipath mitigation. To despread the received pseudonoise (PN) code in CDMA and thus understand the message sent, synchronization (acquisition and tracking) is necessary in priori. In fact, synchronization is a main factor in determining the throughput of the system. We propose a new acquisition procedure in a DS/SS CDMA packet radio system which is able to obtain frame and chip synchronization simultaneously, by using a differentially encoded Barker sequence as the preamble. We also introduce a two-step algorithm and a windowing technique which we found effective in overcoming the partial correlation problem. With simulation studies, we found that the new scheme outperforms other conventional schemes both under a frequency selective fading channel and an AWGN channel