Event Triggered Rx Window Scheduling for RPL-Based IoT Networks

Abstract

Energy efficiency remains a fundamental challenge in battery-operated, resource-constrained sensor nodes, where the combination of IEEE 802.15.4 with 6LoWPAN and the Routing Protocol for Low-Power and Lossy Networks (RPL) has become the standard networking architecture. Prolonged idle listening is a major source of energy loss in constrained sensor nodes. Existing energy-efficient communication strategies primarily optimize routing or duty-cycling independently, without coordinating receiver activity with application-layer event generation. The proposed Event-Triggered Receive Window (ET-RxW) targets receiver-side energy consumption. Receiver activation is aligned with anticipated publication events rather than periodic wake-up schedules. As a result, unnecessary receiver activity during idle periods is eliminated, substantially reducing radio duty-cycling overhead while preserving reliable connectivity and packet delivery. ET-RxW was integrated into the Contiki-NG networking stack and evaluated in the Cooja simulator using Zolertia Z1 motes. Experimental results show a 96% reduction in Radio-Rx energy consumption compared with baseline RPL, while maintaining a 100% Packet Delivery Ratio (PDR) and a convergence time of 14 seconds. A formal analytical energy model was also developed to estimate receiver energy consumption from duty-cycle parameters. Its close agreement with the simulation results confirms the validity of the proposed approach, supporting long-term energy assessment and practical deployment of battery-powered IoT networks.