Toward greenfield time and wavelength division multiplexed passive optical network (TWDM-PON) deployment in access segment, optimal network planning, and resource provisioning need to be explored in the planning phase to reduce capital expenditure (CapEx) and operational expenditure (OpEx). To address the issue, we propose an integer linear programming (ILP)-based optimization framework to design cost-efficient adaptive multi-stage TWDM-PON architecture, where an optimal number of cascaded splitting stages are used to minimize the combined expenditure comprising the CapEx and OpEx. Point-to-point WDM overlay over TWDM-PON is incorporated, wherein we reserve some wavelengths per optical line terminal (OLT) port to equip the heavily loaded (congested) optical network units (ONUs) with dedicated wavelengths. The ILP model offers the complete interconnection details from OLT to all ONUs providing the minimum combined expenditure, and selects the optimal number and locations of remote nodes (RNs) among the candidate RN locations for passive device placement, the types (either arrayed waveguide grating or power splitter) and splitting ratios of passive devices, and the number of splitting stages. Network constraints, such as the minimum guaranteed traffic rate to each ONU, the maximum number of ONUs with dedicated wavelengths per OLT port, and the maximum number of users per OLT port are taken into consideration. We compare the performance of the proposed TWDM-PON design model with the existing studies on greenfield PON design in terms of the cost savings, methodology features, and limitations. The proposed ILP model is further extended to design cost-optimal single-stage and adaptive multi-stage time division multiplexed PONs (TDM-PONs), and the expenditure for all models are estimated. We also investigate the variation in signal-to-noise ratio due to variation in the number of cascade stages. The models provide globally optimal solutions within a reasonable time bound with all constituent sub-problems and constraints jointly taken into consideration.

中文翻译：

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具有PtP WDM覆盖的自适应多级TWDM-PON的成本优化架构设计

为了在接入阶段进行绿地时间和波分复用无源光网络（TWDM-PON）部署，需要在规划阶段探索最佳网络规划和资源配置，以减少资本支出（CapEx）和运营支出（OpEx）。为了解决这个问题，我们提出了一个基于整数线性规划（ILP）的优化框架来设计具有成本效益的自适应多级TWDM-PON架构，其中使用了最佳级联拆分级数来最小化包含CapEx的组合支出和OpEx。结合了TWDM-PON上的点对点WDM覆盖，其中我们为每个光线路终端（OLT）端口保留一些波长，以为重载（拥塞）光网络单元（ONU）配备专用波长。ILP模型提供了从OLT到所有ONU的完整互连详细信息，从而提供了最小的组合开销，并在用于无源设备放置的候选RN位置中选择了远程节点（RN）的最佳数量和位置，类型（阵列波导光栅或功率分配器）和无源设备的分配比以及分配级数。考虑网络限制，例如到每个ONU的最小保证业务速率，每个OLT端口具有专用波长的ONU的最大数量以及每个OLT端口的最大用户数。我们在节省成本，方法学特征和局限性方面，将拟议的TWDM-PON设计模型的性能与现有的未开发PON设计研究进行了比较。提出的ILP模型进一步扩展到设计成本最优的单级和自适应多级时分复用PON（TDM-PON），并估算了所有模型的支出。我们还研究了级联级数变化引起的信噪比变化。这些模型在合理的时间范围内提供了全局最优的解决方案，同时考虑了所有构成子问题和约束。