Fine Timing Synchronization Using Power Delay Profile for OFDM Systems

Abstract

Timing synchronization is more critical in orthogonal frequency division multiplexing (OFDM) systems than in single carrier systems. In this paper, a timing estimation scheme is derived from maximum likelihood estimation (MLE) using power delay profile. It is implemented using a delay locked loop (DLL) to achieve fine timing synchronization for OFDM systems. With this scheme, the mean-square error of symbol timing estimation is decreased by orders of magnitude when compared to the simple peak-finding scheme in multipath fading channels. This scheme also shows higher tracking accuracy for symbol timing drift caused by the sampling clock frequency offset.