摘要
提出了一种改进的适用于高速相干通信长时延扩展稀疏信道的自适应判决反馈均衡器(DFE)。基于最优化前馈滤波器、反馈滤波器与信道冲激响应之间的关系,分析了不同强度的前达(precursor)响应分量对前馈与反馈滤波器稀疏性的影响。给出了根据信道冲激响应确定携带重要能量抽头系数位置的详细理论分析。改进的DFE仅对这些重要抽头系数进行迭代运算,较之传统的DFE,复杂性大为减小,且没有明显性能损失。实测信道仿真证实了该方法的有效性。
In our opinion, conventional adaptive DFE needs to be and can be improved so as to exploit fully the long sparse wireless channels in high-speed digital communication. Threshold DFE （TDFE）, a type of DFE, has tried to modify DFE in order to exploit the sparseness of the long sparse channel in such a way that the positions of the significant taps of the feedback filter （FBF） can be predicted according to the postcursor of channel impulse response （CIR）. However, in our opinion, TDFE＇s hypothesis that the strength of precursor is considerably smaller than the main response is not always valid. Based on the relationships between the optimal feedforward filter （FFF） and FBF on the one hand and the CIR on the other hand, influence of the precursor on the FBF is studied. The results show that most tap coefficients of the FBF are insignificant in case of sparse channels, and the positions of the significant taps are determined by the strength of the precursor and the CIR. We give a fairly detailed theoretical analysis on how to determine the positions of these significant taps. Our modified DFE only depends on the predicted significant taps to exploit the sparseness of the channel, so as to reduce the computational cost considerably. Though there may be a very small cost in mean square error （MSE） performance, our modified DFE also has another advantage of faster convergence rate in that it needs only to process considerably fewer tap coefficients, thus improving tracking capabilities for time varying channels. Computer simulations confirm the above advantages of our modified DFE over the conventional adaptive DFE including TDFE.
出处
《西北工业大学学报》
EI
CAS
CSCD
北大核心
2006年第2期185-189,共5页
Journal of Northwestern Polytechnical University
关键词
高速无线数字通信
稀疏信道
自适应判决反馈均衡器
high-speed wireless digital communication, sparse channel, adaptive decision feedback equalizer （DFE）
