FREQUENCY OFFSET RESISTANT RECEPTION ALGORITHM FOR ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEMS

Performances of the orthogonal frequency division multiplexing (OFDM) systems are very much sensitive to the frequency offset. In the system with differential detection at the receiver, if the phase reference is not stable, due to Doppler effect, fading, or the difference between the oscillators' frequencies at the transmitter and the receiver, the performance improvement may be obtained by using more than two consecutive symbols within the multiple-symbol differential detection (MSDD). A novel approach, based on fast MSDD algorithm with frequency offset hypotheses (HFMSDD), that provides reception of OFDM/MDPSK signal with much higher carrier frequency offset than MSDD-OFDM receiver, is proposed in this paper. Performance of proposed receiver and MSDD-OFDM receiver, are very close only for low frequency offsets. However, proposed receiver operates well in a significantly wider frequency offset range, without the need for any pilot symbols, therefore without any bandwidth efficiency loss. Numerical results are presented to illustrate the effectiveness of the proposed scheme.