DS-SS code acquisition based on simultaneous search and verification

We propose a two-dwell acquisition system with a serial search that operates simultaneously with verification. This system employs two correlation blocks: one for search and the other for verification. The search block continuously searches for the time instants at which the partial correlation value exceeds a time-varying threshold, and at those instants, the verification block is reset and reinitiated until code acquisition is declared by the verification. The time-varying threshold is updated depending on the partial correlation. The mean acquisition time for AWGN and multiple access environment is evaluated by computer simulation and is compared with that of a two dwell system which alternates search and verification modes. The results indicate that the proposed system can perform much better than the conventional one.