Peak AoI-Aware Network Lifetime Maximization in Underwater Acoustic Sensor Networks

Underwater acoustic sensor networks (UASNs) have been proposed to monitor underwater environment for various purposes, e.g., scientific, commercial, military, and so on. However, high dynamic of underwater acoustic links, long propagation delays, and limited bandwidth challenge the application of UASNs for underwater state monitor, particularly for the states that are sensitive to information freshness. In addition, in battery-limited UASNs, the lifetime of underwater sensor nodes (USNs) significantly affects the sustainability of underwater monitor and information delivery. To prolong the lifetime of UASNs constrained by information freshness, a distributed path selection problem is studied. In special, to reliably deliver the underwater state update information to the monitor center deployed on the water surface, a link-level handshake and stop-and-wait mechanism is used. Considering the high dynamic of the underwater environment, the path decision is made between directly transmitting from the source to the sink node, or relaying through a neighbor USN. We formulate the path selection problem in UASNs as a peak age of information (AoI)-aware network lifetime maximization problem. Then, a distributed and cooperative scheme, including the energy-consumption-variance minimization (ECVM) and partial particle swarm optimization (PPSO) algorithms, is proposed to solve the problem. Simulation studies have been conducted to illustrate the efficiency of the proposal.