Energy-efficient Resource Directory Update Scheme for Constrained Application Protocol in Internet of Things

In this paper, we present an energy-efficient resource directory update (ERDU) scheme for the constrained application protocol (CoAP) in Internet of Things (IoT), which is designed to prevent unnecessary energy consumption caused by dead nodes and the frequent transmission of update messages. The ERDU scheme improves the energy efficiency of centralized resource discovery procedures in the CoAP via two main mechanisms: (1) dead node detection and (2) update period adaptation. The former detects dead servers and removes their resource from resource directory (RD) entries to prevent the unnecessary retransmission of the client. The latter adjusts the update period of the server on the basis of its current energy level. Simulation results show that the energy efficiency of the ERDU scheme is better than that of the legacy RD update mechanism.