【摘要】 针对载波频率偏移导致正交平分多路系统的接收信号幅度下降并产生载波间干扰这两个缺陷,建立精确的数学模型,进行详细分析,推导出存在频率偏移时系统信噪比的近似计算公式,定量地估计载波频率误差对系统性能影响,研究表明,与单载波系统相比,OFDM系统对载波频率误差更为敏感,且与调制方式和调制星座数有关,为了避免信噪比的严重恶化,必须尽可能地减小载波频率偏差,选择适当的调制方式。更多还原

【Abstract】 For the two destructions caused by a carrier frequeacy offset in orthogonal frequency division multiplexing (OFDM) systems: the reduction of signal ampltude and the introduction of ICI from the other carriers, a exact model is made. After analyzed in detail, approximate formulas of calculating system SNR was deduced, with these formulas, effects of the carder frequency offset is estimated quantificationally. Comparing with signal carder system, OFDM is more sensitive to frequency offset. The sensitivity is also related to modulation mode and constellation size. In order to avoid severe degradation, the frequency offset should be decreased and proper modulation model should be selected.更多还原