A frequency synchronization method for 3GPP LTE OFDMA system in TDD mode

In this paper, we propose a coarse and fine frequency synchronization method which is suitable for the 3rd Generation Partnership Project (3GPP) long term evolution (LTE) orthogonal frequency division multiple access (OFDMA) system in time division duplexing (TDD) mode. In general, primary synchronization signal (PSS) correlation based estimation method and cyclic prefix (CP) correlation based tracking loop are applied for coarse and fine frequency synchronization in 3GPP LTE OFDMA system, respectively. However, the conventional coarse frequency synchronization method has performance degradation caused by fading channel and signal to noise ratio (SNR) loss. Also, the conventional fine frequency synchronization method cannot guarantee stable operation in TDD mode because there is no signal in uplink subframe. Therefore, in this paper, we propose enhanced coarse and fine frequency synchronization methods which can estimate more accurately in low SNR and high speed channel environments and has stable operation for TDD frame structure, respectively. By computer simulation, we show that the proposed methods outperform the conventional methods, and verify that the proposed frequency synchronization method can guarantee stable operation in 3GPP LTE OFDMA system in TDD mode.