AN OFDM INTEGER MULTIPLE FREQUENCY OFFSET ESTIMATION METHOD

摘要

This invention relates to an OFDM integer multiple frequency offset estimation method in the technical field of telecommunications. The method is based on a N-point synchronous training symbol, which is equally divided into L subdivisions. The receiving end reconstructs M OFDM symbols from the N-point symbols, and each constructed OFDM symbol has L points. Based on the fractional multiple frequency offset value estimated from forgoing modules, a new FFT algorithm structure capable of compensating fractional multiple frequency offset is designed to demodulate part of the reconstructed OFDM symbols by introducing the fractional multiple frequency offset modifying processing to the conventional FFT structures. The part of the reconstructed OFDM symbols are extracted in a way of random-selecting or equal-interval-selecting or continued-selecting from the M reconstructed OFDM symbols. The results of the demodulation are processed using square-combination, then the frequency point corresponding to the peak of the combined demodulated results is the integer multiple frequency offset estimation value. To further reduce computational complexity of this invention, an adaptive algorithm based on reliable decision feedback is employed. This invention has the advantages of less computational complexity and lower estimation error rate, so it is of high value for application in OFDM systems.