空间激光通信中带LDPC编码的网络业务传输设计  

Design of Network Service Transmission with LDPC Coding in Space Laser Communication

作　　者：张晓乐 谭晓川 李哲 ZHANG Xiaole;TAN Xiaochuan;LI Zhe(Hebei Key Laboratory of Photonic Information Technology and Application,The 54th Research Institute of CETC,Shijiazhuang 050081,China)

机构地区：[1]中国电子科技集团公司第五十四研究所、河北省光子信息技术与应用重点实验室,石家庄050081

出　　处：《光通信研究》2024年第6期1-6,共6页Study on Optical Communications

摘　　要：【目的】无线激光通信受大气衰减和大气湍流等因素影响会产生一定程度的误码,往往需要增加纠错编码来提高信号传输质量。低密度奇偶校验码(LDPC)具有接近香农极限的性能,其纠错能力随码字长度的增加会显著提高。对于信息段长度较大的编码,每个编码对应一个以太网帧时,其编解码效率会受到严重影响。对以太网帧的传输方法进行设计,使得不同速率和长度的以太网帧均可充分发挥编解码效率,对于提高以太网数据源的传输速率至关重要。【方法】文章在数据位宽为16 bit的LDPC(4050,2700)编码基础上,对千兆网业务传输方法进行设计。对各个模块之间功能进行清晰划分,在模块内部采用状态机进行设计,使得设计过程中出现的问题可以快速定位,具有很好的开发效率。在发射端设定合适的操作周期对以太网帧进行处理,通过组帧、拼包和填充随机序列等操作,使得对于不同帧长和速率的以太网业务均可自适应匹配LDPC编码模块信息段长度,使LDPC编码的效率得到充分利用。在接收端通过解帧操作即可恢复出各个以太网帧。【结果】最后,文章在XILINX的现场可编程门阵列(FPGA)板卡上对设计方案进行了实物验证,使用千兆网测试仪,对不同帧长以太网数据的传输速率进行测试,结果表明其均可达到千兆网的极限速率1 Gbit/s。对视频和文件等不同业务进行测试,均可进行传输。【结论】文章针对信息段长度大于以太网帧长而设计的以太网业务传输方法,能够适应不同长度、速率和业务的以太网数据传输,并充分发挥编/解码模块的效率,满足无线激光通信中对于高速千兆以太网业务传输的需求。【Objective】Affected by factors such as atmospheric attenuation and atmospheric turbulence,wireless laser communication will produce a certain degree of bit error,and it is often necessary to add error correction codes to improve the signal transmission quality.Low Density Parity Check codes(LDPC)have performance close to the Shannon's limit,and their error-correcting ability will increase significantly with the increase of codeword length.For codes with a large length of information segment,when each code corresponds to an Ethernet frame,its encoding efficiency will be seriously affected.Designing the transmission method for Ethernet frames in a way that allows both different speeds and lengths of Ethernet frames to fully leverage the encoding and decoding efficiency is crucial for enhancing the transmission rate of Ethernet data sources.【Methods】Based on the LDPC(4050,2700)encoding with a data bit width of 16 bit,this paper designs a gigabit network service transmission method.The functions of each module are clearly divided,and the state machine is used in the design of the module.Therefore,the problems in the design process can be quickly located,and the development efficiency is very high.Setting an appropriate operational cycle at the transmitting end to process Ethernet frames,through operations such as framing,packet assembly,and filling with random sequences,enables Ethernet traffic of different frame lengths and rates to adaptively match the information segment length of the LDPC encoding module,thereby fully utilizing the efficiency of LDPC encoding.Each Ethernet frame can be finally recovered by deframing at the receiving end.【Results】Finally,this article verified the design scheme on the Field Programmable Gate Array(FPGA)board of XILINX,and tested the transmission rate of Ethernet data with different frame lengths by using a gigabit network tester.The results show that the data rate can reach the limit rate of 1 Gbit/s.Afterwards,different services such as video and files are successfully

关 键 词：以太网 低密度奇偶校验码 现场可编程门阵列 激光通信 高速率 

分 类 号：TP393.11[自动化与计算机技术—计算机应用技术]