高速光通信低复杂度软信息解调技术  

Low Complexity Soft Information Demodulation Technology for High Speed Optical Communication

作　　者：黄健 朱齐雄[1,2] 陈登超 HUANG Jian;ZHU Qixiong;CHEN Dengchao(FiberHome Telecommunication Technologies Co.,Ltd.,Wuhan 430205,China;Wuhan Fisilink Microelectronics Technology Co.,Ltd.,Wuhan 430205,China)

机构地区：[1]烽火通信科技股份有限公司,武汉430205 [2]武汉飞思灵微电子技术有限公司,武汉430205

出　　处：《光通信研究》2024年第1期64-71,共8页Study on Optical Communications

摘　　要：【目的】常用的max-log-map与log-map算法相比降低了软信息计算复杂度,但对高阶正交幅度调制(QAM)资源消耗仍较大,如8QAM、16QAM概率整形(PS)和64QAM PS。【方法】8QAM采用星座区域划分的方式,文章中,软信息采用接收符号到最近比特0与比特1中垂线的距离信息表示,利用角度旋转和区域对称性简化计算距离信息;非麦克斯韦玻尔兹曼(MB)分布的16QAM PS和64QAM PS,比特1所在区域两侧边缘之间的中心界线与区域两侧比特0之间的中心界线不再重合,对区域进行合并近似,处理两界线间区域归属,展开max-log-map算法因式简化距离差计算软信息;基于MB分布的16QAM PS和64QAM PS的软信息可由非MB分布的软信息表达式化简得到。【结果】经上述简化后,与max-log-map算法相比,8QAM软信息计算乘法次数48次和加减法次数75次分别缩减为12和16次,解调性能仅退化约0.05 dB;MB分布的16QAM PS乘法次数192次和加减法次数260次分别缩减为2和4次,解调性能仅退化约0.05 dB;更高阶的64QAM PS资源消耗缩减程度更大,乘法次数1152次和加减法次数1542次分别缩减为3和6次。【结论】文章提出了适用于8QAM、MB分布的16QAM PS、MB分布的64QAM PS、非MB分布的16QAM PS和非MB分布的64QAM PS软信息计算方法。当概率满足MB分布时,非MB分布的软信息计算方法可转化为MB分布计算方法;当PS因子为0时,基于MB分布的表达式可转化为均匀分布软信息计算式,非MB分布、MB分布和均匀分布的软信息计算可使用同一电路统一设计,提高电路复用率,降低硬件资源消耗。【Objective】The commonly used max-log-map algorithm reduces the complexity of soft information computation compared to the log-map algorithm.However,it still consumes a large number of resources for high-order Orthogonal Amplitude Modulation(QAM),such as 8QAM,16QAM Probability Shaping(PS),and 64QAM PS.【Methods】8QAM adopts the method of constellation region division,and the soft information is represented by the distance information from the received symbol to the perpendicular of the nearest bit 0 and bit 1.The distance information is simplified and calculated using angle rotation and regional symmetry.For 16QAM PS and 64QAM PS distributed by non Maxwell Boltzmann(MB)distribution,the central boundary between the edges of the region where bit 1 is located and the central boundary between bit 0 on both sides of the region bit 1 no longer coincide.The region merging approximation is used to handle the region ownership between the two boundaries,and the max-log-map expression is factorized to simplify the distance difference to calculate the soft information.The soft information of 16QAM PS and 64QAM PS based on MB distribution can be obtained by simplifying the soft information expression of non MB distribution.【Results】After the above simplification,the multiplication and addition/subtraction times of 8QAM soft information calculation were reduced from 48 and 75 times to 12 and 16 times respectively with a degradation of only about 0.05 dB;The 16QAM PS with MB distribution has 192 multiplication times and 260 addition/subtraction times reduced to 2 and 4 times,respectively,resulting in a degradation of only about 0.05 dB.Higher order 64QAM PS has a greater reduction in resource consumption reduced the multiplication and addition/subtraction times from 1152 and 1542 times to 3 and 6 times,respectively.【Conclusion】This article proposes a soft information calculation method suitable for 8QAM and MB distribution of 16QAM PS,MB distribution of 64QAM PS,non MB distribution of 16QAM PS,and non MB distributi

关 键 词：光通信 数字信号处理 正交幅度调制 对数似然比 概率整形 

分 类 号：TN929[电子电信—通信与信息系统]