Time synchronization and frequency offset estimation in OFDM systems

The present invention provides a method for performing joint time synchronization and carrier frequency offset estimation in a wireless communication system, comprising steps of: in a transmitter; performing frequency domain spreading and interleaving on input data by using a predetermined spreading factor (SF) to generate a frequency domain training symbol, performing an Inverse Discrete Fourier Transformation (IDFT) on the generated frequency domain training symbol to generate a first time domain training symbol, reversely copying the generated first time domain training symbol such that a complete training sequence is formed; and in a receiver: detecting the average power of received signals to determine the presence of a training sequence, and performing coarse frame synchronization, performing joint fine frame synchronization and carrier frequency offset estimation based on a received training sequence, and compensating for the carrier frequency offset based on the carrier frequency offset estimation result so as to eliminate the carrier frequency offset. In addition, the present invention also provides an apparatus for performing joint time synchronization and carrier frequency offset estimation and a method for generating a training sequence.