Analysis of the effect of timing synchronization errors on pilot-aided OFDM systems

Timing synchronization errors degrade the performance of an OFDM receiver by introducing inter-carrier-interference and inter-symbol-interference. These errors can occur due to either an erroneous initial synchronization or a change in the power delay profile of the channel. In this paper, mathematical analysis of the effect of timing errors on the performance of an OFDM receiver is provided. Exact expressions for the resulting average signal to interference ratio (SIR) were derived in the presence of timing errors. Then the effect of timing errors on the performance of a pilot-aided channel estimator is analyzed. Expressions for the average power of the channel estimation error in the presence of timing errors and noise are derived for a frequency selective fading channel. The results show the non-symmetric effect of timing errors on the performance of an OFDM system. Furthermore, they show the super-sensitivity of pilot-aided channel estimator to such errors. Finally simulation results confirm the analysis.