Design and analysis of a probability-based data forwarding scheme in wireless sensor networks

To increase the end-to-end packet delivery ratio in wireless sensor networks with unreliable communication links, existing routing protocols often use the data forwarding schemes based on a hop-by-hop ACK-based retransmission mechanism. However, these schemes may waste a considerable amount of energy for data transmissions, especially when the link quality is low for ACK transmissions. This paper proposes a novel probability-based data forwarding (PDF) scheme to minimize the energy consumption for unnecessary data retransmissions. In PDF, a retransmission threshold is set in each sensor depending on the probability of sending out a data packet successfully, thus becoming probability-based. The threshold is a number of data retransmissions sufficient for a data packet to arrive successfully at a next hop. The sender node stops sending a data packet after the threshold even if it does not receive an ACK message. To make PDF adaptable to various requirements of applications, we introduce 2 variations of PDF: energy-efficient PDF and reliable PDF. Probabilistic analysis and simulation results demonstrate that the proposed PDF schemes can save much energy and significantly increase the energy efficiency compared to the pure-ACK-based scheme when both schemes use the two well-known data forwarding metrics, PRR× Distance and NADV, in the network layer by up to 140.50% and 57.55%, respectively.