一种基于对数似然比的解扩方法  

A Despreading Method Based on Log-Likelihood Ratio

作　　者：刘郑[1] 郑建生[1,2] 雷莉[2] 郭文飞[1] 

机构地区：[1]武汉大学卫星导航定位技术研究中心,湖北武汉430079 [2]武汉大学电子信息学院,湖北武汉430079

出　　处：《北京理工大学学报》2015年第4期427-431,共5页Transactions of Beijing Institute of Technology

基　　金：国家自然科学基金资助项目(61273053);中国博士后科学基金资助项目(2013M542061;2014T70738);湖北省自然科学基金资助项目(2014CFB727)

摘　　要：提出了一种基于对数似然比的解扩方法.该方法基于解调输出的软信息(即对数似然比)解扩且输出也为软信息,理论分析表明该方法的误码率能达到最佳误码率性能.在不同调制方式下对该解扩方法的误码率进行了仿真,结果显示该方法的误码率曲线与最佳误码率理论曲线重合,且比传统基于硬信息的解扩方法的性能优化2dB左右.利用该方法可以方便地与软信息输入输出的Turbo信道编译码技术相结合.A despreading method based on log-likelihood ratio was proposed.The despread was based on the output soft information of demodulation（namely the log-likelihood ratio）,in which the output was also soft information.Theoretical analysis indicates that the method has the best performance of bit error rate.The simulation results of the BER performance curve under different modulation mode indicate that the BER curve of the method almost overlaps with the best performance BER curve in theory,and the method has about 2dB performance optimization compared with the conventional despreading method based on hard information.The method can easily combine with channel coding technology such as Turbo code that based on soft information input and output.

关 键 词：对数似然比 软信息 调制方式 TURBO码 

分 类 号：TN911.72[电子电信—通信与信息系统]