PERFORMANCE ANALYSIS FOR AN ADAPTIVE FILTER CODE-TRACKING TECHNIQUE IN DIRECT-SEQUENCE SPREAD-SPECTRUM SYSTEMS

This paper investigates tracking of direct-sequence spread-spectrum (D S/SS) signals based on an adaptive filtering technique, It is shown th at a recently proposed hardware for code acquisition is also capable o f code tracking, and, hence, by performing both acquisition and tracki ng with the same circuitry, a significant simplification in the overal l DS/SS receiver structure is gained. Analytical results show that the proposed scheme has good tracking performance, as measured by the hol d-in time and the false alarm penalty time, and is less sensitive to v ariations in the signal-to-noise ratio (SNR) compared to conventional delay-locked loops (DLL's). Moreover, simulation results show that the proposed adaptive filter tracking scheme has a smaller residual track ing error than that produced by a conventional maximum-likelihood esti mator (MLE).