Fuzzy Control-Based Channel-Aware Reliable Routing Protocol for Underwater Sensor Networks

Underwater wireless sensor networks (UWSNs) are increasingly being applied in various fields, and an efficient routing protocol is critical for ensuring reliable data transmission in UWSNs. Due to the dynamic topology and limited energy conditions of UWSNs, the design of routing protocols usually comprehensively consider multiple metrics such as node mobility and energy efficiency to achieve reliable routing decisions. However, these parameters have different characteristics and often involve trade-offs. For example, energy efficiency prioritizes nodes with higher remaining energy for data forwarding to extend network lifespan but may result in selecting nodes with poor channel conditions, reducing reliability. Conversely, prioritizing link quality often favors well-connected nodes, which may have lower energy due to frequent use. Traditional additive composite functions struggle to balance these trade-offs dynamically, potentially leading to suboptimal routing decisions. Moreover, the rapid changes of acoustic channels in underwater environments can result in time-varying link quality. To address these issues, this article proposes a fuzzy control-based channel-aware reliable routing protocol for underwater sensor networks (FCCR). The proposed protocol can coordinate and handle multiple metrics to optimize the selection of the next-hop node, thereby improving data forwarding efficiency and reliability. Additionally, in UWSNs, node movement or failure may cause the communication link between nodes to break, resulting in routing void. The protocol also incorporates a void recovery mechanism, which effectively addresses the routing void problem. The field experiment and simulation results demonstrated that the proposed protocol performs well in terms of packet delivery ratio (PDR), average end-to-end delay (EED), and energy efficiency.