Pilot based synchronization in OFDM systems using maximum likelihood estimation

Orthogonal frequency division multiplexing (OFDM) based communication systems are very efficient in combating inter-symbol interference (ISI) in frequency-selective channels. However, carrier frequency offset (CFO) severely affects system performance by destroying the orthogonality between the OFDM subcarriers. In this paper, we estimate the CFO in a block OFDM system using maximum-likelihood estimation (MLE) and pilot subcarriers. Through simulations, we then show the deleterious effect of the CFO on the bit error rate (BER) and subsequently, the performance improvement after CFO compensation.