Analytical Evaluation of Timing Offset Error in OFDM System

Abstract

This paper proposes an idea of developing a model of estimating timing offset error of OFDM (Orthogonal Frequency Division Multiplexing) system without the use of additional pilots relying on inherent characteristics of the OFDM signal. An analytical expression has been derived and formulated to analyze the effect of bit error rate (BER) due to timing offset introduced by the transmission channel. This will help in determining the exact length of cyclic prefix to be added to each OFDM symbol to avoid misinterpretation by the receiver. The performances have also been evaluated under coded (convolution) and uncoded systems. The introduction of channel coding decreases this basic impairment of OFDM systems significantly. Simulated results show that the symbol error rate (SER) linearly depends on timing offset. It is expected that further works on the proposed estimated method will lead to a standard model so that at the receiving end the effect of timing offset can be eliminated totally.