HFC-CATV网络上行通道噪声特性分析及抗干扰技术研究

【作者】 花汉兵；

【导师】 王建新；

【作者基本信息】 南京理工大学 ， 信号与信息处理， 2003， 硕士

【摘要】 论文对HFC-CATV上行信道噪声特性和抗干扰技术进行了研究。首先分析了上行信道噪声漏斗效应现象，讨论了HFC网络中噪声干扰的来源、成因和特点，其次以数学公式及物理定律为理论基础建立了上行信道噪声模型，接着研究上行信道噪声对QPSK、16QAM调制技术的影响。分析与仿真表明，冲击脉冲的出现频度越高或每个冲击脉冲的能量越大，则误码性能劣化越显著；而窄带连续波干扰的特征函数与高斯白噪声一样，所以误码曲线的形状也一样，随着比特信噪比的增大，误码率下降很快，但随着窄带连续干扰波数目的增多，误码性能明显变差。通过分析得到QPSK系统的抗干扰性能要优于16QAM。最后，采取了同步码分多址技术和非线性自适应滤波技术来抑制冲击干扰和窄带连续波干扰。更多还原

【Abstract】 The noise characteristics and the anti-interference techniques of the HFC-CATV upstream channel are studied in this thesis. Firstly, the noise "funnel effect" phenomenon is analyzed and the sources, the cause and the characteristics of the noise interference in the HFC network are discussed. Secondly, based on the related mathematical formulas and physical laws, the noise models of the upstream channel are set up. Then, the effects that the noises in the upstream channel have on the QPSK and 16QAM modulation techniques are studied. The simulation results show that the more frequently the impulse emerges or the greater the energy of each impulse, the more obviously the bit error rate degrades . The characteristic function of the narrow-band continuous wave interference is the same as that of gaussian white noise, so the shapes of their bit error graph are the same. With the increase of the Eb/N0, the bit error rate declines quickly, but with the increase of the number of the narrow-band continuous wave, the performance on the bit error rate degrades greatly. The study results have shown that the anti-interference performance of the QPSK system is better than that of the 16QAM system. Finally, The S-CDMA and the adaptive nonlinear filter techniques are used to restrain the impulse interference and the narrow-band continuous wave interference.更多还原