低莱斯因子下的时频联合MMSE均衡算法  

Time-frequency Joint MMSE Equalization Algorithm under Low Rice Factor

作　　者：毕号旗 杨宝林 向新[1] 郑万泽 鞠明 Bi Haoqi;Yang Baolin;Xiang Xin;Zheng Wanze;Ju Ming(Aeronautical Engineering College,Air Force Engineering University,Xi’an,Shaanxi 710038,China;School of Telecommunications Engineering,Xidian University,Xi’an,Shaanxi 710071,China;PLA 91313 Unit,Beijing 100038,China)

机构地区：[1]空军工程大学航空工程学院,陕西西安710038 [2]西安电子科技大学通信工程学院,陕西西安710071 [3]空军91313部队,北京100038

出　　处：《信号处理》2020年第10期1751-1759,共9页Journal of Signal Processing

摘　　要：针对低莱斯因子的慢衰落时变多径信道条件下,难以有效利用信号能量,导致系统误码性能差,单纯的基于最小均方误差准则均衡(Minimum Mean Squared Error,MMSE)技术不能够有效降低误码率的实际问题。在构建信道等效模型的基础上,提出了一种利用硬判决符号重构信道,在两个信道长度内比较改判信号误差信息的时频联合判决两轮次MMSE均衡算法。仿真结果表明:通过均衡处理后的低莱斯因子信道能逼近高莱斯因子的误码特性,当信噪比为20 dB时,不同莱斯因子下QPSK信号的误码率均降低至10-4以下,且在一个数量级内。当信噪比为2~6 dB时,系统误码率分布在10-1~10-3之间,要低于信号在自由空间传播的误码率,说明MMSE均衡充分利用了多径分量的能量,获得了信噪比增益。For the slow fading time-varying multi-path channel with low Rician factor,the signal energy cannot be effectively used,and the system error performance is poor.The purely equalization based on the minimum mean squared error(MMSE)technology cannot effectively reduce the error.On the basis of constructing the channel equivalent model,a two-round MMSE equalization algorithm is proposed that uses hard decision symbols to reconstruct the channel and compares the time-frequency joint judgement of the error information of the modified signal within two channel length.The simulation results show that the low Rice factor channel after equalization can approach the bit error characteristics of the high Rice factor.When the signal-to-noise ratio is 20 dB,the bit error rate of QPSK signals under different Rice factors is reduced to 10-4 below and within an order of magnitude.When the signal-to-noise ratio is 2~6 dB,the system bit error rate is lower than the bit error rate of the signal propagating in free space range from 10-1 to 10-3,indicating that MMSE equalization makes full use of the energy of the multipath component and obtains the signal-to-noise ratio gain.

关 键 词：多径信道 最小均方误差准则 时频联合判决 均衡 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]