摘要： 自适应判决反馈均衡器(DFE)能跟踪信道时变响应并自动调整抽头系数，解决数字通信中因信道衰减和噪声引起的符号间干扰问题，从而大大降低通信系统误码率。针对在自适应均衡过程中均衡器阶数难以确定的问题，根据最优估计理论，分析判决反馈均衡器结构，研究DFE的抽头长度对均衡器均方误差性能的影响，在此基础上提出阈值可变动态长度算法，找出最小均方误差与滤波器阶数之间的折中。Matlab分析和仿真结果显示，当信道衰减和符号间干扰较严重时，均衡器阶数收敛在30阶左右，且误差可以收敛在较小范围内跟踪信道响应，并在瞬时累计均方误差准则下收敛到滤波器最优阶数。
关键词:
自适应判决反馈,
均衡器,
符号间干扰,
串行/解串器,
阶数可变,
累计均方误差
Abstract: In digital communication systems, Decision Feedback Equalizer(DFE) is usually used to track time-varying response of channel, adaptively adjust filter tap coefficient and remove Inter Symbol Interference(ISI), caused by channel attenuation and noise. Aiming at the problem of difficulty of ascertaining the length of equalizer, this paper uses the method of theoretical analysis to analyze the structure of DFE deeply and research adaptive decision feedback equalization algorithm based on optimal estimation theory and length of filter coefficient influence on Mean Square Error(MSE). On this basis, Varying Threshold-Dynamic Length Algorithm(VT-DLA) is proposed for finding tradeoff between minimum mean square error and optimal filter length. Matlab analysis and simulation result shows that the length of equalizer can converge to 30 taps approximately under the serious channel attenuation and noise, it can track channel response and converge to optimal filter length in some instantaneous accumulative MSE.
Key words:
adaptive decision feedback,
equalizer,
Inter Symbol Interference(ISI),
serializer/deserializer,
order variable,
Accumulative Mean Square Error(AMSE)
中图分类号: