Fast Acquisition Algorithm for PN Sequences

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In CDMA mobile communications, the acquisition procedure is the first and most fundamental function to be done before establishing connection. And the acceleration of the procedure is the one of the most important problems to reduce the communication overhead.The purpose of this research is to propose a new acquisition algorithm for PN sequences, such as m-sequence, GMW-sequence etc., by utilizing their internal composite structures of PN sequences and show that the proposed algorithm can provide faster and better acquisition performance than the conventional algorithms.In the fiscal year 2004, we extended our previous basic algorithm, which assumes chip synchronization, to a realistically feasible fast algorithm, which does not require chip synchronization, and examined its fundamental properties. Through theoretical analyses for the mean acquisition time and its variance, we could show that the proposed algorithm exhibits sufficiently good performance compared to the conventional methods.In the fiscal year 2005, the proposed fast acquisition algorithm in the previous year, after incorporating the time-over function, was examined in detail through computer simulations. We also compared the computational complexity of the proposed algorithm with those of the conventional ones. It is concluded that the proposed fast acquisition algorithm can provide much better performance in mean acquisition time and its variance with a quite small increase of computational complexity.