Time and frequency synchronization techniques for OFDM systems

Orthogonal frequency division multiplexing (OFDM is a multi-carrier modulation technique which uses several orthogonal subcarriers to transmit/receive a high data rate signal. Proper synchronization must be done for the adequate working of the system. Initially Schmidl and Cox proposed a method, in which with the help of a training symbol, with two identical halves synchronization is achieved. Thereafter many methods have been developed. The aim of this paper is to study and compare various methods for time and frequency synchronization. In addition we provide the effects of adding identical parts to the preambles on the Schmidl and Cox proposed training symbol. The synchronization techniques are examined in Gaussian and Multipath fading environments for comparison. The results of the performance comparison are presented in terms of the timing metric defined differently by various methods.