A novel transform domain fully digital PN code tracking loop
Due to the nature of the code waveforms typically used in direct-sequence spread-spectrum (DS/SS) communication systems, the issue of pseudo-noise (PN) code synchronization is important. In this paper, fine synchronization (code tracking) is considered. A novel frequency domain approach to PN code tracking is proposed. The new method is based on the fuzzy technique. The code-timing is recovered by a tracking loop including the frequency domain fuzzy code phase estimator, the variable delay line and so on. The new tracking loop is fully digital and programmable, and hence is more stable to changes in environment parameters, which often influence the performance of analog loops. The structure and algorithm for the new tracking loop are presented and its performance is evaluated. Simulation results show that the frequency domain fuzzy tracking loop provides good performance even at low E/sub b//N/sub 0/ when the delay variation is slow.