A delay-tolerant framework for integrated RSNs in IoT

The Internet of Things (IoT) represents an evolutionary vision that promises to identify and connect physical objects and devices. This vision faces many challenges in terms of integrating technologies, especially RFID-sensor networks (RSNs). In this paper, we introduce a framework for node deployment and delay-tolerance in RSNs under the IoT paradigm. Our framework is comprised of two components. The first is SIWR, a novel Smart Integrated WSNs and RFIDs architecture that classifies nodes into light nodes and super integrated nodes. SIWR employs an optimal linear programming formulation to cost-efficiently place integrated RFID readers. However, integrated IoT architectures face significant connectivity challenges. IoT settings assume no guaranteed contemporaneous end-to-end path between node pairs. To this end, in the second part of our framework, we introduce DIRSN, an optimized delay-tolerant approach for integrated RFID-sensor networks. This is a novel scheme for data routing and courier nodes' selection in RSNs. DIRSN's formulation minimizes delay across the network without violating the main dense-deployment and load-balancing requirements. In addition, DIRSN builds on SIWR's novel architecture to locate the best set of couriers that promise to provide connectivity. Our combined approach is compared to three types of RSN integration architectures and the results show that our architecture and courier selection approaches perform substantially better than other architectures in terms of minimizing delay, cost, packet loss, and in handling extensive traffic demands. (C) 2012 Elsevier B.V. All rights reserved.