###### Abstract  
As advancements in autonomous underwater vehicle (AUV) technology unfold, the role of underwater wireless sensor networks (UWSNs) is becoming increasingly pivotal. However, the high energy consumption in these networks can significantly reduce their operational lifespan, while latency issues can impair overall network performance. To address these challenges, a novel mixed packet forwarding strategy is developed, which incorporates a wakeup threshold and a dynamically adjusted access probability for the cluster head (CH). This approach aims to conserve energy while maintaining acceptable network latency levels. The wakeup threshold restricts the frequency of state switching for the CH, thereby reducing energy consumption. Meanwhile, the dynamic access probability regulates the influx of packets to mitigate system congestion based on current network conditions. Furthermore, to accommodate the network's varied transmission demands, packets generated by sensor nodes (SNs) are categorized into two types according to their sensitivity to latency. A discrete\(-\) time queueing model with preemptive priority is then established to evaluate the performance of different packets and the CH. Numerical results show how different parameters affect network performance and demonstrate that the proposed mixed packet forwarding mechanism can effectively manage the trade\(-\)off between latency and energy consumption, outperforming the traditional mechanism within a specific range of parameters. underwater wireless sensor networks; priority scheduling; access probability; wakeup threshold; queueing theory +
Footnote †: journal:  
0000-0001-5000-0000-0000-0000-0000-0000-0000-0000-0000-0000-00000-00000-00000-00000-00000-00000-00000-00000-00000-00000-00000-000000-0  
UWSN allows for the modulation of sensor node depths to gather oceanic data across various depths. The structure of the three\(-\)dimensional static UWSN is similar to that of the three\(-\)dimensional UWSNs equipped with AUVs, with the key difference being the substitution of stationary sensor nodes with mobile AUVs in the latter. This three\(-\)dimensional UWSN, enhanced by AUVs, represents an advancement over static networks, potentially boosting the communication capabilities of UWSNs. However, deploying these three\(-\)dimensional UWSN structures is challenging, and they are susceptible to damage due to the unique characteristics of underwater environments. Therefore, existing research mostly focuses on the two\(-\)dimensional static UWSN structure. Energy consumption optimization is a core and urgent issue that needs to be addressed in UWSNs. Because SNs are typically deployed in environments that are difficult to access physically, such as deep\(-\)sea or remote water areas, the initial configuration of batteries often limits the energy supply of these nodes, and it is difficult to carry out subsequent energy replenishment or replacement [5; 6; 7]. Therefore, the energy consumption of SNs directly determines the lifecycle and stability of the network, and the development of energy\(-\)saving technologies is particularly crucial. Cluster structure is the most efficient energy\(-\)saving method in UWSNs, whose core principle is to organize a large number of SNs into clusters [8]. Each cluster is led by a cluster head (CH), responsible for coordinating and managing the data collection, processing, and transmission of nodes within the cluster [9]. In actual underwater network environments, data sensitivity to transmission latency often varies [10]. Sudden events in environmental monitoring (such as ocean pollution spills, early warning of natural disasters, etc.) usually require more rapid forwarding. In contrast, information with lower time sensitivity (such as long\(-\)term climate trend analysis and monitoring of periodic changes in ecosystems) can tolerate a certain degree of latency. Therefore, designing a reasonable data classification mechanism can more intelligently allocate limited resources and improve the network's overall performance.