Abstract
A fundamental challenge in underwater wireless sensor networks (UWSNs) is that acoustic links are subject to high transmission power with high channel impairments. These channel impairments result in higher error rates and temporary path losses which restrict the efficiency of these networks. Besides this, the availability of limited resources and continuous node movements are major threats for reliable data deliveries. With these constraints, it is a difficult task to design a protocol which has the ability to maximize the reliability of these networks. In this paper we provide a reliability model in order to insure reliable data deliveries from sensor nodes to surface sink. For this purpose, we propose an algorithm which determines the suitable data packet size for efficient data transfer. It uses a two-hop acknowledgment (2H-ACK) model where two copies of the same data packet are maintained in the network without extra burden on the available resources. The findings on the relationship between data packet size, throughput, bit error rate (BER), and distance between both communicating nodes are also presented.