A Sampling Frequency Offset Estimation Method for High-speed Power Line Communication System

High speed Power Line Carrier Communication (HPLC) uses Orthogonal Frequency Division Multiplexing (OFDM) technology that is sensitive to frequency offset. Due to cost reasons, the crystal oscillator performance of power line carrier communication system is limited, and the crystal oscillator frequency offset gradually accumulates and increases with time, causing sampling frequency offset and having a significant impact on the demodulation performance of the system. In order to reduce the impact of sampling frequency offset on demodulation performance, this paper proposes a sampling frequency offset estimation and compensation algorithm based on the equalized signal. This algorithm first equalizes the preamble symbols, then utilizes the equalized preamble symbols for sampling frequency offset estimation, then fully exploits the subcarrier accumulation effect within the effective bandwidth to reduce the impact of noise on the estimation results. The method is simulated in Additive White Gaussian Noise (AWGN) channel and multipath channel respectively. The simulation results show that the method of equalization before estimation improves the accuracy of sampling frequency offset estimation, thus improves the demodulation performance of power line carrier communication system, and the improvement is particularly significant in multipath channel.