Practical Time Synchronization for OFDM Systems on Mobile Channel

This paper presents practical time synchronization algorithm for mobile channel in wireless orthogonal frequency division multiplexing (OFDM) system such as 3G-LTE [1]. We first analyze the method of general time synchronization algorithm in OFDM systems. The analysis will show that the calculated time value for synchronization is unstable and inadequate. This instability of synchronization time value is generated by the variation of multipath channel in which max power path is changed with time. We show how proposed algorithm reduces the instability of synchronization time. Results of simulation show that proposed algorithm reduces the instability of synchronization time and improve time tracking performance considerably. Consequently demodulation performance is also enhanced and overall communication system can operate more efficiently. Because proposed timing synchronization algorithm decides synchronization time considering channel characteristics, controlled synchronization time is extremely stable. Especially, 16-QAM and 64-QAM modulation schemes for high data rate transmission is more sensitive to timing error, therefore proposed time synchronization algorithm supports to keep high data rate system performance stable.