CELR: Connectivity and Energy aware Layering Routing protocol for UANs

Underwater Acoustic Networks (UANs) use acoustic waves for communications, which consume excessive energy. Conversely, the nodes in UANs have scarce energy resources, thus energy saving is a vital objective of routing protocol design for UANs. Due to the high cost, nodes are usually deployed sparsely. Moreover the nodes in water can move with water current or other underwater activities. Consequently, the data transmission with traditional routing protocol is subject to the routing problem of “void area” in UANs. In this paper, we propose a Connectivity-and-Energy-aware Layering Routing (CELR) protocol to achieve two objectives of energy-saving and reliable routing. Addressing the routing problem of “void area”, a connectivity-aware layering algorithm is presented based on the minimum hop-count from the sink to underwater nodes. To reduce the energy consumption, on the basis of connectivity aware layering algorithm, a connectivity and energy aware layering algorithm is proposed. Further, taking the residual energy and hop-distance into account, we present a CELR routing protocol for UANs. Experiments results show that the CELR protocol outperforms the depth-based routing (DBR) and layer-based and energy-efficient routing (LEER) protocol in terms of packet delivery rate, average energy consumption and end-to-end delay.