The adaptive beacon interval mechanism in the APID protocol calculates the dynamic beacon period through neighbor factors and node factors. The design of these two factors considers which network and node states are considered, and how they jointly affect the length of the beacon period?
In the APID protocol, the adaptive beacon interval mechanism is designed to allow each UUV to adjust its beacon transmission frequency based on its current network environment and individual status. The neighbor factor primarily reflects the density and mobility dynamics of the surrounding nodes. Specifically, it considers how many neighbors a node currently has and how fast those neighbors are moving relative to itself. A higher neighbor factor indicates either a near-ideal neighbor density or significant relative motion in the vicinity, both of which suggest that topology information may become outdated quickly and thus more frequent beacons are needed. The node factor, on the other hand, captures the node’s own condition, including its remaining energy and the magnitude of its recent speed change. A node with higher residual energy or a sharp change in velocity is more capable and more necessary to update its status frequently. These two factors are combined to jointly determine the beacon period. When the sum of the neighbor factor and the node factor is large, indicating high dynamics or high forwarding suitability, the beacon period is shortened to improve neighbor synchronization. Conversely, when the sum is small, the beacon period is lengthened to conserve energy and reduce unnecessary overhead. This joint adaptation ensures that beaconing is both responsive to network changes and efficient in energy usage.
