Analyses and Suppression Method of Frequency Offset and Timing Offset in FH-OFDM System

Recently, FH-OFDM (frequency hopping orthogonal frequency division multiplexing) system has been widely used in communication system. However, FH-OFDM system is sensitive to frequency offset and timing offset, which are inherently unavoidable in wireless mobile communication systems and can seriously degraded system performance. So, research on estimation and compensation of these offsets is of great importance. In this paper, a novel joint method for estimating carrier frequency offset and timing offset is proposed. This algorithm exploits pilots to estimate the offsets, and compared with other methods, the processing can be completed in one symbol time period. Thus, this method can be used in both static and ergodic channel. The estimation can be divided into frequency offset estimation and timing offset estimation. Also, both frequency offset and timing offset estimation are divided into two steps: coarse frequency offset estimation step, fine frequency offset estimation step, fraction timing offset estimation step and integer timing offset estimation step. Through the computer simulations, the suggested algorithm shows very good performance results both in AWGN and multipath environments.