Reliable sensor-to-sink data transfer with duty cycles for Wireless Sensor Networks

Wireless Sensor Networks (WSNs) are generally energy and resource constrained. However, packet level reliability is an important quality-of-service metric for any networking application. Existing sensor networking protocols that provide reliable data transfer for sensor-to-sink traffic either provide reliability at the event level or are not energy-efficient. Employing duty cycles improves energy-efficiency but significantly degrades the network performance, particularly packet delivery ratio for higher network traffic. We propose a cross layered approach that utilizes inactive nodes as monitors to assist in quick packet-loss detection and recovery while employing duty cycles for energy-efficiency. To improve packet level reliability, monitors passively overhear the communication of active nodes for detecting packet losses and also act as alternate forwarders to overcome congested spots. We implemented the proposed approach in ns-2 simulator and conducted extensive experimentation: results show that monitors provide a significant improvement in packet delivery ratio while providing energy savings.