引入混沌机制处理HFC网络回传噪声问题

Chaos to reduce upstream noise converge in hybrid fiber coaxial networks

为克服在光纤同轴电缆混合(HFC)网络进行双向改造时会遇到的汇集噪声问题,引入混沌机制,将有用信号调制到参数空间中去,利用混沌的分叉特性和参数敏感性处理回传噪声问题。通过对Duffing方程的分析给出了这种方法的理论推导,并且给出了具体实践中的模型,同时分析了实际运用中可能出现的阵发混沌现象以及仿真结果。混沌振子首次被引入数字系统中,并实现了对四相频移随控(QP-SK)信号的解调。此方法使得在信噪比很低的情况下仍旧能够检测出回传信号,使原有网络得到充分利用,双向改造更加简便易行。

Twoway hybrid fiber coaxial (HFC) network systems have problems with convergence of upstream noise. The upstream noise problem was analyzed by adding chaos to the upstream node of an HFC network. The upstream signal was detected by modulating the signal to the parameter space and analyzing the bifurcation character of the chaos. A model was developed for the chaotic response and the intermittent chaotic noise problem. Chaos was applied to the digital system as the demodulator of the quarter phase shift keying (QPSK) modulated signal. The signal can be detected even when the SNR (signal noise rate) is very low, so the upstream noise convergence can be solved without extensive changes to the original network. 