自由空间光通信中的PPM迭代软解调算法  

PPM Iterative Soft Demodulation Algorithm in Free-space Optical Communication

作　　者：张鼎臣[1] 周小林[1] 杜建洪[1] 

机构地区：[1]复旦大学通信科学与工程系,上海200433

出　　处：《计算机工程》2013年第4期1-4,共4页Computer Engineering

基　　金：国家自然科学基金资助项目(60802011);国家"863"计划基金资助项目(2011AA100701);国家科技重大专项基金资助项目(2012ZX03001013-004;2011ZX03003)

摘　　要：为避免自由空间光通信中的信道衰落,提高抗干扰能力,采用脉冲位置调制(PPM),提出一种基于光子计数的单数据流软入软出迭代解调算法。在受限散粒噪声Poisson信道模型下,推导迭代解调算法,并基于该算法给出4PPM的简化方案。针对重复码和串行级联码分别进行数值仿真并分析其性能,实验结果表明,该简化算法能降低计算复杂度,且易于硬件实现。To overcome the channel fading and improve the anti-interference capability in free-space optical communication, a coded Pulse Position Modulation（PPM） photon-counting based iterative demodulation scheme by utilizing Soft-input Soft- output（SISO） for single data stream is proposed, On the assumption of shot noise limited Poisson channels, the iterative demodulation algorithm is derived and on the basis of it, a simplified scheme is proposed for 4-ary PPM. The numerical results under the conditions of Repetition Code（RC） and Serial Concatenated Code（SCC） also with analysis of system performance are illustrated. The simulations show that the scheme can provide a relatively good system Bit Error Rate（BER） performance with low computational complexity and is easy for hardware realization：

关 键 词：迭代译码 脉冲位置调制 光子计数 自由空间光通信 软解调 级联码 

分 类 号：TN929.12[电子电信—通信与信息系统]