基于HINOC协议的SNR估计算法

同轴电缆宽带接入网络(HINOC2.0)[1],HINOC2.0系统采用正交频分复用(OFDM)技术,可实现高速可靠的数据传输。本文讨论了HINOC2.0标准下行链路中信噪比(SNR)估计的算法[2,3],包括时域上的SNR估计和频域上各子载波组的SNR估计。频域估计SNR时,第一种方法利用接收端估计信道得到的H值直接进行相应计算,第二种方法提取接收端探测帧和空白帧中的有效数据进行计算。仿真结果表明,在AWGN信道下,时域和频域估计得到的SNR值均与理论值相近;在衰落信道下,时域估计结果出现错误,频域估计的两种方法中,第一种方法得到的SNR值部分正确,第二种方法得到的SNR值比第一种更为准确。

HINOC 2.0 is designed for the access network based on coaxial cables, it adopts Orthogonal Frequency Division Multiplexing （ OFDM ） technology, enabling high-speed and reliable data transmission.In this paper, SNR estimation methods are diseusssed in the HINOC 2.0 system, including SNR estimation in time domain and frequency domain. The SNR on each subcarrier group is different. Two estimation methods are presented in frequency domain, the first one uses the channel value H calculated by the receiver directly, the second method extracts valid data from probe frame and idle frame. The simulation results show that： under the AWGN channel, estimation results in time domain and frequency domain are both accurate compared to the theoretical values. Under fading channels, estimation results of the time domain method are inaccurate. On the other hand, the first frequency domain method also results in quite large errors, while the results of the second frequency domain method are more reliable than those of the first.