Gamma-Gamma模型下采用PPM调制的MIMO-FSO系统误时隙率分析  

Performance analysis of MIMO-FSO systems based on PPM modulation and Gamma-Gamma distribution model

作　　者：王红星[1] 徐建武[1] 孙晓明[1] 胡昊[1] 吴晓军[1] 

机构地区：[1]海军航空工程学院电子信息工程系,山东烟台264001

出　　处：《系统工程与电子技术》2012年第2期385-390,共6页Systems Engineering and Electronics

摘　　要：分析了在Gamma-Gamma分布下基于脉冲位置调制(pulse position modulation,PPM)方式的多输入输出自由空间光学(multiple input multiple output free space optics,MIMO-FSO)通信系统模型。首先推导了单输入单输出(single input single output,SISO)-PPM系统的误时隙率(slot error rate,SER)计算公式,以此作为参考,在独立同分布和独立分布参数不同情况下,分别推导出MISO-PPM、SIMO-PPM和MIMO-PPM系统的平均SER计算公式,并用数值仿真的方法,分析了它们的平均SER性能。仿真结果表明,在Gamma-Gamma分布模型下,采用多发多收的方法确实能有效提高FSO系统的平均SER性能,如在误时隙率为10-4时,M=2、N=2的MIMO-PPM系统在信道分布参数相同和不同时,与SISO-PPM相比,分别能节省信噪比50dB和65dB左右。实际应用中,M和N分别取3或4就基本足够,对无线光通信系统的理论分析和系统设计具有一定的指导意义。The multiple input multiple output free space optics （MIMO-FSO） system model is analyzed under the Gamma-Gamma distribution channels and pulse position modulation （PPM）. The SER calculating formula of single input single output （SISO）-PPM systems is derived firstly, then as a benchmark, under the cases of both independent with identical distribution （IID） and independent with different distributions（IDD）, the average slot error rates （SER） of MISO-PPM, SIMO-PPM and MIMO-PPM systems are derived respectively. Simulations of the average SER performances of these systems are done. The simulation results show that, under Gamma-Gamma distribution, the average SER is indeed improved in MIMO systems. When SER is at 10-4 , the average SER of the MIMO-PPM system with M=2 and N=2 is improved by about 50 dB and 65 dB under IID and IDD respectively. In practical designs, M and N are enough to set to 3 or 4 respectively. The obtained conclusion is significant to the analysis and design of FSO systems.

关 键 词：无线光通信 脉冲位置调制 多输入多输出 误时隙率 

分 类 号：TN929.12[电子电信—通信与信息系统]