关键词: 正交频分复用, 频率偏移, 子载波间干扰, 时域加窗, 信号干扰比

Abstract: The Inter Carrier Interference（ICI） caused by frequency deviation will have an impact on the performance of the Orthogonal Frequency Division Multiplexing（OFDM） communication system. For solving this problem, an algorithm based on symmetric inter carrier is proposed. The proposed algorithm modulates the opposite symbols onto the symmetric inter carriers; at the receiver, the demodulated symbols are combined linearly. For reducing the ICI further, the algorithm is combined with windowing in time-domain. That is the symbols are multiplied by raised cosine function before they were transmitted. In the algorithm simulation experiments, the algorithm based on symmetric inter carrier decreased the Inter Carrier Interference（ICI） coefficient compared with the typical self-cancellation scheme; the side lobe of the OFDM symbol spectrum attenuated fast after windowing, and the maximum could be －40 dB; for the Signal to Interference power Ratio（SIR）, the algorithm after windowing could improve about 8 dB compared with the typical self-cancellation scheme; in the case of lager Signal to Noise Ratio, it also improves the Bit Error Ratio performance. The simulation results show that the proposed algorithm can suppress the ICI and improve the anti-jamming performance of OFDM system.

Key words: Orthogonal Frequency Division Multiplexing（OFDM）, frequency deviation, Inter Carrier Interference（ICI）, time-domain windowing, Signal to Interference power Ratio（SIR）