Time Synchronization Properties in OFDM System Based on Cyclic Prefix

The acceptable performance of the receiver side in communication systems can be achieved only if synchronization between the transmitter and the receiver exists. In this paper, two techniques that remove the influence of symbol time offset using cyclic prefix are analyzed to accomplish synchronization - accurate conduct of an orthogonal frequency division multi-plexing (OFDM) system. The first technique is based on finding the maximum correlation between two blocks of samples and the second one is based on finding the similarity between two blocks, which is maximized when the difference between them is minimized. Two types of channel conditions are observed. The first one uses only additive white Gaussian noise, while the second one also uses the channel impulse response of the Rayleigh fading channel. By adding Rayleigh channel effect, both estimation performances, by calculating correlation and difference, deteriorate if sufficient level of signal-to-noise ratio and proper length of cyclic prefix are not provided.