Resilience by multi-connectivity network design in industrial IoT environments

无线传感器网络在工业环境中的弹性运行是一个重要的要求，因为它允许无线系统在中断事件后提供足够的服务水平，并自动恢复到稳定状态。为了提高无线链路的可靠性和可用性，一种有用的技术是从源到融合节点建立多个同步链路和多条边不相交路径。项目的动机源于观察到已建立的链接和路径之间的依赖关系会显著影响最终的可靠性。本项目将通过运用联结理论对这些依赖结构进行基础性的理解。因此，应该部署不同的无线电接入技术，以实现统计独立的连接。对于弹性作业的所有三个阶段，即常规阶段、生存阶段和可恢复性阶段，对多路径和连通性的精心选择进行了建模、分析和优化。首先，该项目开发了节点放置和配置的新算法。通过适应网络环境的微小变化，保证所需的业务功能。安装了监控网络状态和检测中断事件的系统。在检测到网络中多个链路和节点同时出现故障后，系统进入生存性阶段。在此阶段，系统将保持稳定，防止级联故障，同时保持高服务水平的功能。其次，针对这两个目标，在多目标规划框架下对多路径和多连通性进行优化。将网络可扩展性的概念扩展到多路径和多连接环境，并建立了确定性和统计优化模型。第三，在网络稳定后，导出、部署和激活恢复阶段的计划及其相应的目标配置。向这个新配置的过渡必须是无缝的，不能停止系统或导致服务中断，并提供了相应的方法。最后，该项目将在现实工业工厂环境的小规模演示平台上演示开发的算法。计划部署最多10个节点，最多有两个跃点连接到融合中心。将评估其可行性和基本性能。在系统级模拟中，也将演示方法和算法的可扩展性。总体而言，该项目将在可生存性和可恢复性阶段的服务改进方面取得重大进展。还将演示如何通过多路径和多连接技术缩短返回恢复的系统状态的时间。

Resilient operation of wireless sensor networks in industrial environments is an important requirement because it allows the wireless system to provide sufficient service level after a disruptive event and to automatically recover to a stable state. One useful technique to offer higher reliability and availability of the wireless links is to establish multiple simultaneous links and multiple edge-disjoint paths from the source to fusion nodes. The motivation for the project stems from the observation that dependencies between established links and paths significantly impact the resulting reliability. The project will contribute to the fundamental understanding of these dependency structures by applying copula theory. As a result, different radio access technologies should be deployed to achieve statistically independent connectivity. For all three phases during resilient operation, namely regular, survivability, and recoverability phase, the careful selection of multi-path and -connectivity is modeled, analyzed, and optimized. First, the project develops novel algorithms for node placement and configuration. The required service function is guaranteed by adapting to small changes in the network environment. A system for monitoring the network status and detecting disruptive events is installed. After detection of a simultaneous failure of several links and nodes in the network, the system enters the survivability phase. During this phase, the system will stabilize and prevent cascading failure, and at the same time, maintains a high service level function. Second, for both goals, multi-path and -connectivity will be optimized under a multi-objective programming framework. The concept of network extensibility is extended to multi-path and -connectivity environments and both deterministic as well as statistical optimization models are developed. Third, after stabilization of the network, a plan for the recovery phase and its corresponding target configuration is derived, deployed, and activated. The transition to this new configuration must be seamless, without halting the system or causing service interruptions, and according methods are provided. Finally, the project will demonstrate the developed algorithms on a small-scale demonstrator platform in a realistic industrial factory environment. The deployment of up to 10 nodes with at most two hop connections to the fusion centers is planned. The feasibility as well as the fundamental performance will be assessed. In system-level simulations the scalability of the approaches and the algorithms will be demonstrated, too. Overall, the project will show significant gains in terms of service improvement during survivability and recoverability phases. It will also demonstrate how to shorten the time to return to the recovered system state by multi-path and multi-connectivity techniques.