Dynamic Virtual Heat Fields for Void-Avoidance Opportunistic Routing in UASNs

Underwater Acoustic Sensor Networks (UASNs) have attracted considerable attention due to their broad application prospects. However, the challenges of limited battery replacement and unstable communication in underwater environments make it difficult for traditional routing protocols to balance stability and energy consumption under dynamic topologies. To address these challenges, we propose a Dynamic Virtual Heat Field-based Void-Avoidance Opportunistic Routing (DVHVOR) protocol. Inspired by the diffusion of heat from sources to cooler regions in nature, the protocol constructs a virtual heat field to guide efficient data forwarding without relying on precise three-dimensional localization. Specifically, it integrates hop count, residual energy, and depth information into a heat-value metric. The Sink periodically broadcasts packets, forming a dynamic and adaptive virtual heat field across the network. During data transmission, each node selects the neighbor with the highest heat value as the relay and employs a concurrent forwarding mechanism to improve both energy efficiency and adaptability to topology changes. Compared with conventional greedy routing strategies, the virtual heat field provides stable and tunable multi-path guidance.Simulation results demonstrate that, relative to existing protocols, the proposed approach reduces the variance of residual energy by an average of 35.9%, decreases transmission delay by approximately 10.9%, and achieves superior performance across multiple metrics including network lifetime, thereby validating its feasibility and advantages in dynamic and network sparse scenarios.