Energy-Balanced Routing Protocol With Nonuniform Clustering for Underwater Acoustic Sensors Networks

Energy consumption has been the focus of routing protocols in underwater acoustic sensor networks (UASNs), and many cluster-based routing protocols have been proposed to optimize energy consumption. However, there is the “hotspot” problem resulting from frequent data forwarding by cluster heads (CHs) and energy inefficiency caused by the transmission of data packets from shallow water to deep water. Therefore, we propose an energy-balanced routing protocol with nonuniform clustering (ERNC) to balance energy consumption and improve data transmission efficiency. First, without accurate 3-D localization, nodes exchange information with each other, and the combined coordinate of layer ID and hop ID is proposed to represent the node’s location information for subsequent CH selection and intercluster routing. Then, the combined coordinate, residual energy, and node density are considered comprehensively to select CHs for making their distribution uneven and equalizing the energy consumption. In the intercluster routing phase, the next hop candidate node sets with different forwarding priorities are constructed based on nodes’ coordinates to improve the network transmission efficiency. Moreover, we design the different holding times for the next-hop nodes in the same set to balance the energy consumption of CHs. The simulation results show that ERNC can effectively extend the network lifetime and improve the data transmission performance.