Optimal fiber link fault decision for optical 2D coding-monitoring scheme in passive optical networks
Optimal fiber link fault decision for optical 2D coding-monitoring scheme in passive optical networks
复制标题
DOI：
10.1364/jocn.8.000137
复制
发表时间：
2016-03
期刊：
影响因子：
--
通讯作者：
M. Zhu;Jiao Zhang;Dongpeng Wang;Xiaohan Sun
中科院分区：
文献类型：
--
作者：
M. Zhu;Jiao Zhang;Dongpeng Wang;Xiaohan Sun
针对无源光网络（脑桥）中光纤链路的监测问题，提出了几种基于传统OTDR技术的光纤故障监测方案。然而，在树形拓扑PON中，网络管理员很难区分故障发生在哪个光纤链路中。因此，已经提出了一些基于光编码技术的方案来克服光时域反射计在监测点到多点网络中的缺点。在本文中，我们建立了一个数学模型的光学二维编码监测系统的PON，其中包括三个模块：检测脉冲发生器，光编码和传输，光解码和故障识别。分析了任意两个二维码部分重叠时的相关距离表达式和干扰概率。此外，我们推导出的PD（检测概率）和PFA（虚警概率）通过分析目标信号，干扰，和所有可能的噪声，这是用来计算最佳决策概率的封闭形式的表达式。系统性能的信号噪声比，信号干扰比（SIR），和最佳的决策概率方面进行了研究与不同的系统参数，如客户端的分离距离，网络规模，发送脉冲宽度，和发送脉冲功率。仿真结果表明，最佳发射脉冲宽度为TC ≤ 1 ns，信干比下限为~21 dB。最后得出结论，合适的系统变量可以最优选择，以方便最优决策。
Several fiber-fault monitoring schemes based on traditional OTDR technique have been proposed for monitoring fiber links in passive optical networks (PONs). However, in a tree-topology PON, it is difficult for network managers to distinguish which fiber link the fault occurs in. Thus, some schemes based on an optical coding technique have been proposed to overcome the optical time-domain reflectometry disadvantages in monitoring point-to-multipoint networks. In this paper, we develop a mathematical model for an optical 2D coding-monitoring system in PONs which includes three modules: detection pulse generator, optical encoding and transmission, and optical decoding and fault identification. We also analyze the correlation distance expression and interference probability with partial overlap between any two 2D codes. In addition, we derive close-form expressions for PD (detection probability) and PFA (false-alarm probability) by analyzing the target signal, interference, and all possible noises, which are used to calculate optimal decision probability. The system performance in terms of signal-to-noise ratio, signal-to-interference ratio (SIR), and the optimal decision probability are investigated with different system parameters such as client separation distance, network size, transmitted pulse width, and transmitted pulse power. The extensive simulation results show that the optimal transmitted pulse width is TC ≈ 1 ns and the SIR is to a lower bound of ~21 dB. It is concluded that suitable system variables can be chosen optimally to facilitate the optimal decision.