Wireless sensor networks (WSNs), often adhering to a single gateway architecture, constitute the communication backbone for many modern cyber-physical systems (CPSs). Consequently, fault-tolerance in CPS becomes a challenging task, especially when accounting for failures (potentially malicious) that incapacitate the gateway or disrupt the nodes-gateway communication, not to mention the energy, timeliness, and security constraints demanded by CPS domains. This paper aims at ameliorating the fault-tolerance of WSN-based CPS to increase system and data availability. To this end, we propose a replicated gateway architecture augmented with energy-efficient real-time Byzantine-resilient data communication protocols. At the sensors level, we introduce fault-tolerant trustful space-time protocol, a geographic routing protocol capable of delivering messages in an energy-efficient and timely manner to multiple gateways, even in the presence of voids caused by faulty and malicious sensor nodes. At the gateway level, we propose a multigateway synchronization protocol, which we call ByzCast, that delivers timely correct data to CPS applications, despite the failure or maliciousness of a number of gateways. We show, through extensive simulations, that our protocols provide better system robustness yielding an increased system and data availability while meeting CPS energy, timeliness, and security demands.
ASJC Scopus subject areas
- Signal Processing
- Information Systems
- Information Systems and Management
- Computer Science Applications
- Hardware and Architecture
- Computer Networks and Communications