A fast DS/CDMA acquisition scheme based on igniter sequence and distributed samples

This paper introduces a new acquisition scheme called distributed sample acquisition (DSA), which is applicable to the DS/CDMA system with a long-period PN sequence. The DSA scheme employs two new concepts, igniter sequence and distributed samples, for signal acquisition. The igniter sequence is a short-period sequence that conveys the main-sequence samples of the transmitter to receiver in a distributed manner, which are thus called distributed samples. In synchronizing the igniter sequence, we employ normal serial search schemes, but for synchronization of the main long-period PN sequence we employ the novel distributed sample scrambling (DSS) technique. The resulting mean acquisition time of the DSA scheme is dramatically reduced for the long period PN sequence, and the additional circuit complexity for its implementation is very small.