Enhanced coherent delay tracking for direct sequence spread spectrum systems

Abstract

An enhanced coherent delay lock loop (DLL) is proposed for code tracking in direct sequence spread spectrum systems on multipath fading channels. By normalising the estimated tracking error for large values of the power of the tracked path, the proposed loop reduces most of the degradation caused by fading. Moreover, by subtracting an estimation of the multipath bias from the output of the coherent DLL, this enhanced scheme reduces most of the degradation caused by multipath interference.