面向自由空间光通信的PC-STBC方法研究  

Research on PC-STBC method for free space optical communication

作　　者：秦怀军 曹阳[1] 彭小峰[1] 张祖鹏 QIN Huaijun;CAO Yang;PENG Xiaofeng;ZHANG Zupeng(Chongqing University of Technology,Chongqing 400054,China)

机构地区：[1]重庆理工大学,重庆400054

出　　处：《激光杂志》2022年第5期95-100,共6页Laser Journal

基　　金：重庆市教委科学技术项目(No.KJQN201901125);重庆市科委社会事业与民生保障科技创新专项(No.cstc2017shmsA40019);重庆市基础与前沿研究计划项目(No.cstc2019jcy-msxmX0233)。

摘　　要：针对大气湍流对自由空间光通信系统误码率影响较大的问题,提出了一种在多输入多输出系统中将极化编码与空时编码直接级联的方案。在弱湍流信道中,使用高斯近似的方式构造出编码序列并进行极化编码,并使用二进制相移键控对编码序列进行调制,再与空时编码进行直接级联。仿真结果表明:在多输入多输出系统中,码字长度N=1 024时,系统的误码率可下降至10-6级以下;若码字长度N=2 048时,信噪比高于2 dB时,误码率可趋近于0。接收天线数越多,系统的分集阶数越高,系统误码率下降速度变慢,系统整体性能变差。因而该级联方案能够更好地改善系统误码率性能。并且在不同的湍流强度下,表现出对强湍流具有更好的抑制效果,误码率下降更明显。Aiming at the problem that atmospheric turbulence has a great impact on the bit error rate of free space optical communication system,a scheme of directly cascading polarization coding and space-time coding in multi input multi output system is proposed. In the weak turbulent channel,the coding sequence is constructed by Gaussian approximation and polarization coding,and the coding sequence is modulated by binary phase shift keying,and then directly cascaded with space-time coding. The simulation results show that in the MIMO system,when the codeword length n = 1 024,the bit error rate of the system can be reduced to less than 10-6levels;If the codeword length n =2 048 and the signal-to-noise ratio is higher than 2 dB,the bit error rate can approach 0. The more the number of transmit antennas,the higher the diversity order of the system. When the bit error rate tends to 0,a signal-to-noise ratio gain of 1. 5 dB can be obtained. Therefore,the cascade scheme can better improve the bit error rate performance of the system. Under different turbulence intensity,it shows a better suppression effect on strong turbulence,and the bit error rate decreases more obviously.

关 键 词：自由空间光通信 极化码 空时编码 直接级联 

分 类 号：TN929[电子电信—通信与信息系统]