Relay Node Placement Considering Age of Information for Seafloor Optical Wireless Networks

In this paper, we consider the optimal placement problem in seafloor optical wireless networks. In a seafloor optical wireless network, data collected by sensors are forwarded to relay nodes and delivered to a sink node via multiple relay nodes. The performance of data delivery to the sink node depends greatly on the placement of relay nodes. Therefore, this paper formulates an optimization problem in which the objective function is to minimize information freshness, i.e., the age of information. Since this optimization problem is a mixed integer linear problem once the relay node locations are determined, we propose a relay node placement method using a genetic algorithm. In the proposed method, the placement position of the relay node is assumed to be a gene, and the fitness value is obtained by solving the mixed integer programming problem. Through the simulation experiments, we show that efficient data transfer can be achieved by using the proposed method for relay node placement.