A Comprehensive Review on Urban Resilience via Fault-Tolerant IoT and Sensor Networks

Fault tolerance is essential for reliable and sustainable smart city infrastructure. Interconnected IoT systems must function under frequent faults, limited resources, and complex conditions. Existing research covers various fault-tolerant methods. However, current reviews often lack system-level critique and multidimensional analysis. This study provides a structured review of fault tolerance strategies across layered IoT architectures in smart cities. It evaluates fault detection, containment, and recovery techniques using specific metrics. These include fault visibility, propagation depth, containment score, and energy-resilience trade-offs. The analysis uses comparative tables, architecture-aware discussions, and conceptual plots. It investigates the impact of fault tolerance on decision-making in Supervisory Control And Data Acquisition (SCADA) systems, sensor networks, and real-time controllers. Simulation results and logic-based design support the relationships between evaluation metrics. Findings show a common reliance on redundancy and reactive methods. Many techniques fail to address cross-layer propagation, context-aware adaptation, and silent fault impact on user trust. The study combines these overlooked aspects into a system-level framework. This survey identifies performance bottlenecks and supports the design of adaptive, energy-efficient, and transparent IoT systems. The results contribute to bridging technical reliability with public trust, supporting scalable and responsible smart city development.