A Algorithm of Preamble Acquisition Base on Differential Correlation Module for CDMA System

Random access process is one of the basic physical processes of uplink and downlink interaction in CDMA system. When a user terminal connects with the mobile network, the random access process must be included. Traditional direct acquisition algorithm of random access preamble signal can't detect correctly in the presence of large frequency offset. Based on the study of the generation mechanism of the preamble sequence in the upstream random access channel of WCDMA terminals, a two-step cascaded preamble acquisition algorithm based on differential correlation is proposed in this paper. The algorithm overcomes the effect of frequency offset on the performance of the preamble acquisition. The simulation results show that the algorithm has good acquisition performance for the uplink random access preamble signal of the terminal with negative signal-to-noise ratio under the condition of large frequency offset.