# Research on Networking Protocols for Large-Scale Mobile Ultraviolet Communication Networks
###### Abstract
Although the network scale can be expanded by increasing the number of clusters and cluster members, a large number of cluster members are only gathered around the cluster heads, resulting in the fact that the actual coverage area of the network is difficult to effectively expand. In addition, such clustering-based protocols have a high degree of dependence on high-performance cluster heads, which leads to a decrease in the reliability of the protocol and a significant increase in complexity. Refs. [12; 13; 14] implements time division multiple access (TDMA) by allocating channels to nodes, which avoids channel competition and can significantly improve channel utilization. Refs. [15; 16; 17; 18] proposed and refined a MAC protocol that enables competition-free communication in multi-hop networks, eliminating resource wastage caused by competition. The protocol also introduces a bit-by-bit forwarding-based relay mechanism, ensuring data transmission from the source node to the destination node within each time slot. Leveraging the competition-free mechanism, ref. [19] has developed an innovative neighbor discovery algorithm based on the time difference of arrival. The proposed protocol, utilizing the neighbor table, enables efficient shortest path selection throughout the network. This not only minimizes the overall energy consumption but also substantially boosts the data throughput. By striking an optimal balance between energy efficiency and transmission performance, the protocol significantly enhances the network's operational effectiveness and reliability. The aforementioned protocols predominantly focus on small-scale network scenarios, demonstrating satisfactory functionality and reliability within such application environments. However, when applied to large-scale networks, these protocols fail to adequately account for the dynamic growth characteristics of channel resources engendered by network expansion. In particular, in large-scale network environments, the substantial increase in the number of nodes not only significantly elevates the complexity of channel resource allocation and management but also exacerbates the cumulative interference among nodes, which can severely degrade network performance. Evidently, there remains considerable room for enhancing the scalability and adaptability of these protocols in large-scale network scenarios. Furthermore, the performance evaluation and design optimization of existing UV communication network protocols mainly center around static network scenarios, lacking a systematic consideration of mobile network environments. In the practical application of drone group networking, the operational state of the network is influenced by multiple factors such as meteorological conditions and mission requirements, and the spatial positions of drone nodes exhibit a high degree of dynamics and uncertainty. Given the inherent characteristics of limited communication distance and easy signal scattering in UV light communication, changes in the spatial positions of nodes may lead to the interruption of communication links or interference between nodes, thus causing frequent changes in the network topology. In long-distance communication scenarios, data transmission highly relies on multi-level relay forwarding by intermediate nodes. At this time, any change in the position of nodes on the transmission path may result in transmission interference or physical disconnection of communication links, posing significant challenges to the overall communication performance of the network. Therefore, conducting in-depth research on the key parameters affecting network performance in extreme environments and designing dynamic response mechanisms that are both efficient and reliable are essential research steps for constructing a flexible networking protocol system and verifying the practicality of the protocols.