Two chances forwarding in real-time routing for low-duty-cycle sensor networks

Abstract

Duty cycle has been regarded as an efficient way for energy conserving in wireless sensor networks (WSNs). In this paper, we propose a routing protocol framework (RRAD) to achieve the quality of service (QoS) requirements in the timeliness and reliability domains efficiently for asynchronous duty-cycled sensor networks. Firstly, the concepts of the real-time relay probability and E2E reliability are introduced to assist in node forwarding operations. Secondly, we novelly exploit an active slot augmentation mechanism to reduce extra sleep latency caused by unreliable links, with which the end-to-end delay can be decreased by at least two times in experiments. Moreover, by exploiting the asynchronous waking up time in duty-cycled networks, we propose a lightweight potential forwarder discovering algorithm to offer nodes another chance to be the forwarder. Finally, we demonstrate the efficiency of the proposed RRAD protocol in terms of routing latency and reliability through comprehensive experiments.