光学学报, 2009, 29 (1): 132, 网络出版: 2009-02-10
自由空间光通信中的混合空时编码
Hybrid Space-Time Code for Free Space Optical Communication
光通信 多输入多输出 空时编码 脉冲位置调制 分组干扰抑制 optical communication multiple input multiple output space-time code pulse position modulation group interference suppression
摘要
在分析了大气对光信号的影响之后, 利用脉冲位置调制(PPM)的正交性构造了一种适合于强度调制/直接检测式光通信的正交空时编码, 并将其引入分层空时编码的首层以增加第一层信息符号的分集度; 其次采用分组干扰抑制的方法消除其它层对信号的干扰, 利用空时分组码(STBC)和分层空时编码的译码方法并结合最大似然判决准则恢复出原始信号。最后, 利用仿真实验进一步验证了该方法的可行性。结果表明:在自由空间光通信中, 混合空时编码方案的性能明显优于传统BLAST码方案的性能。
Abstract
An orthogonal space-time block code suitable for intensity modulation/direct detection optical communication system is constructed by using orthogonality of pulse position modulation (PPM) after analyzing the effect of atmosphere on the optical signal. The technique is applied to the first layer of the layered space-time code (LST) to increase the diversity of the information symbol. The effect of other layers on the symbol is eliminated by using group interference suppression (GIS). The signal is recovered by combining the decoding method of space-time block code (STBC) and Bell Labs Louyered Space-Time (BLAST) and maximum likelihood decision rule. The feasibility of the technique is proved by the simulation experiment. It shows that in free space optical communication the error rate performance of hybrid space-time code is better than BLAST.
王惠琴, 柯熙政. 自由空间光通信中的混合空时编码[J]. 光学学报, 2009, 29(1): 132. Wang Huiqin, Ke Xizheng. Hybrid Space-Time Code for Free Space Optical Communication[J]. Acta Optica Sinica, 2009, 29(1): 132.