MPPM光通信系统中多对一映射的概率整形研究  

Probabilistic Shaping of Many-to-One Mapping in Multipulse Position Modulation Optical Communication Systems

作　　者：向劲松[1] 巫晋 Xiang Jinsong;Wu Jin(School of Communications and Information Engineering,Chongqing Universityof Posts and Telecommunications,Chongqing 400065,China)

机构地区：[1]重庆邮电大学通信与信息工程学院,重庆400065

出　　处：《中国激光》2025年第1期169-177,共9页Chinese Journal of Lasers

摘　　要：在空间光通信系统中,传统的多脉冲位置调制(MPPM)存在星座冗余的问题,只能使用星座点子集进行映射。鉴于此,本研究结合概率整形中多对一映射的思想,提出了多对一MPPM调制(MTO-MPPM),以提高MPPM的信息传输速率。仿真结果表明:MTO-MPPM的模糊比特数越少,性能的提升越明显。在MPPM调制阶数M为6、8、11的双脉冲MPPM中,MTO-MPPM与传统MPPM相比,信息传输速率分别提升了33%、25%和20%,每传输1 bit信息所需的光子数分别减少了0.7 dB、0.2 dB、0.2 dB。由于MTO-MPPM可充分利用冗余星座点,其调节信息速率的性能比传统的卷积码删余或MPPM变阶方式更优。Objective In space optical communication systems,multipulse position modulation(MPPM)has garnered notable attention due to its advantages,including high reliability,spectral efficiency,strong anti-interference capabilities,and low power consumption.However,traditional MPPM constellation points are not integer powers of 2,following by a partial mapping of MPPM constellation points due to constellation redundancy.Existing research has explored constellation point selection strategies for MPPM and proposed methods such as the Blahut-Arimoto algorithm and compressed sensing to maximize the constrained channel capacity.However,no feasible schemes have been proposed for addressing nonstandard constellation points in MPPM.Based on the traditional MPPM system and many-to-one mapping in probabilistic shaping,we propose a many-to-one mapping MPPM(MTO-MPPM)system to mitigate constellation redundancy and enhance the information transmission rate of MPPM.In traditional MPPM systems,information transmission rates are improved primarily through two methods:by increasing coding efficiency via convolutional code deletion,which,however,does not alter the channel capacity of MPPM,or by reducing the order of MPPM,which,however,is constrained by the number of mapping bits.Therefore,we compare the transmission rate adjustment performance of the proposed MTO-MPPM system with traditional convolutional code deletion and variable-order MPPM rate adjustment to highlight the advantages of MTO-MPPM.Methods The performance of the MTO-MPPM system is analyzed based on the SCPPM system.By increasing the number of bit symbol groups,the MTO-MPPM system incorporates more constellation points compared to traditional MPPM.For instances exceeding the available constellation points in MPPM,bit symbol groups are mapped to the same constellation points,addressing the issue of constellation points not being integer powers of 2.To avoid excessive fuzzy bits introduced by many-to-one mapping,the MTO-MPPM system restricts each constellation point to mapping

关 键 词：空间光通信 多脉冲位置调制 星座冗余 概率整形 多对一映射 

分 类 号：TN929.12[电子电信—通信与信息系统]