空间光通信中基于多输入多输出的级联码方案研究  

Cascade Scheme Based on Multiple-Input Multiple-Output in Spatial Optical Communication

作　　者：曹阳 张勋 彭小峰 任发韬 Cao Yang;Zhang Xun;Peng Xiaofeng;Ren Fatao(School of Electrical and Electronic Engineering, Chongqing University of Technology, Chongqing 400054, Chin)

机构地区：[1]重庆理工大学电气与电子工程学院,重庆400054

出　　处：《光学学报》2018年第1期69-76,共8页Acta Optica Sinica

基　　金：国家自然科学基金(61205106);博士后科学基金(2014M552329);重庆市教委基金(KJ120827);重庆市教委科学技术研究项目(KJ1500934;KJ1709205)

摘　　要：针对多输入多输出自由空间光通信系统中误码扩散的问题,提出一种卢比变换码与奇偶检验码级联的级联码方案,该方案通过在卢比变换编码包后增加一位校验元来定位并删除其中错误的编码包,同时仿真比较卢比变换码与级联码的性能。在不同多输入多输出组数和通信距离的系统下对级联码进行仿真验证,模拟不同大气湍流强度信道。仿真结果表明:译码开销不超过0.5时,级联码可提升译码成功率;在相同湍流环境下,相比于天线个数为2×2的系统,天线个数为3×3的系统大约有3dB的编码增益,且采用级联码后,当误码率为10-5左右时,编码增益提升范围为0.5dB^2dB;在强湍流环境下,当天线个数相同时,随着通信距离的增大,相比于卢比变换码,级联码仍有一定的编码增益优势。Aiming at the problem of error diffusion in multiple-input multiple-output free-space optical（MIMOFSO）communication system,we propose a cascaded code（LT-PC）scheme of the Luby transform（LT）code and the parity check（PC）code.The LT-PC scheme can locate and delete wrong packets by adding a checker based on LT code.The performance of the LT code is compared with that of the LT-PC code.The LT-PC code is verified by the simulation under the systems with different number of MIMO groups and communication distances.Different atmospheric turbulence intensity channels are also simulated.The results show that the LT-PC code can improve the success rate of decoding when the decoding overhead is less than 0.5.In the same turbulence environment,the system with antenna number of 3×3 has about 3 dB coding gain compared with the system with antenna number of2×2.After using the LT-PC code,the improving range of the coding gain is 0.5 dB^2 dB when the bit error rate is about 10-5.In the strong turbulence environment,the LT-PC code still has certain advantages over the LT code with the increase of the communication distance when the numbers of antennas are the same.

关 键 词：光通信 级联码 多输入多输出自由空间光通信 误码扩散 误码率 通信距离 

分 类 号：TN911.22[电子电信—通信与信息系统]