Li Ruijie, Ding Shengli, Dang Anhong
J Opt Soc Am A Opt Image Sci Vis. 2017 May 1;34(5):798-803. doi: 10.1364/JOSAA.34.000798.
This paper investigates a detection scheme without channel state information for wireless optical communication systems. Employing conventional on-off keying signals, we supposed that conditional probability density function P(r|0) is much bigger than P(r|1) when r<0. Under this assumption, the suboptimal maximum likelihood scheme is obtained by utilizing the probability density function without channel information. Theoretical analysis shows the performance of the proposed scheme is close to the maximum likelihood symbol-by-symbol detection. Compared with the maximum likelihood symbol by symbol detection, Monte Carlo simulations show that the performance of the proposed scheme is about 0.62 dB loss for a gamma-gamma channel with a Rytov variance of 1 at the signal-to-noise ratio of 2 dB, but the efficient algorithm makes the real-time implementation of detection based on maximum likelihood feasible. Besides, the experiment is set up under 2 Gbps, and the experimental results match well with that of the theory and simulation.
本文研究了一种用于无线光通信系统的无信道状态信息检测方案。采用传统的开关键控信号，我们假设当r<0时，条件概率密度函数P(r|0)远大于P(r|1)。在此假设下，通过利用无信道信息的概率密度函数获得了次优最大似然方案。理论分析表明，所提方案的性能接近最大似然逐符号检测。与最大似然逐符号检测相比，蒙特卡罗仿真表明，在信噪比为2 dB时，对于Rytov方差为1的伽马-伽马信道，所提方案的性能损失约为0.62 dB，但高效算法使基于最大似然的检测实时实现成为可能。此外，实验在2 Gbps下进行设置，实验结果与理论和仿真结果匹配良好。
