Despreading code synchronization technique utilizing discrete sampled data and its application to DS-CDMA systems using RF direct under-sampling

A novel synchronization technique for despreading codes for DS-CDMA utilizing discrete data obtained by sampling is proposed. The technique enables despreading codes to be synchronized with received signals without using additional tracking circuits even when sampling phases deviate from phases of received signals. We applied this synchronization technique to a DS-CDMA receiver using an RF direct under-sampling. Experimental results of tests of the CDMA receiver fabricated with FPGA devices showed that the synchronization technique was effective for despreading codes.