## 2 Simulation Model Setting for Underwater Electric Field Communication  
In underwater node communication, although MAC protocols applicable to underwater communication networks, both domestically and internationally, consider long propagation delays, node energy efficiency, and transmission efficiency, there are few MAC protocols designed for underwater node mobility. Especially when AUVs participate in networking, the nodes in underwater dynamic self-organizing networks move relatively quickly, resulting in most traditional MAC protocols no longer being applicable. For MAC protocols that require centralized nodes, strict scheduling order, and relatively fixed topology, they cannot support the implementation and deployment of dynamic self-organizing networks. Most communication protocols are mainly applied to underwater acoustic communication, with few targeting underwater electric field communication protocols. The MAC protocol was mainly designed to improve channel utilization efficiency and maximize fairness for channel users, but there is a problem of wasting channel resources in time in underwater environments. There are currently two main underwater channel allocation techniques for electronic communication systems: dynamic media access control and static channel allocation. For underwater robots, static channel allocation is not suitable and there is a problem of channel resource waste due to disconnection or joining the network during deployment or insufficient energy during the movement process; for dynamic media access control, the most typical CSMA/CA protocol has been widely used. This protocol does not allocate channel media to any node, but adopts a random channel allocation method, which can fully utilize the channel. And in order to solve the problem of channel conflicts, the article considers the mobility of underwater electric field communication in multi-node networking, designs a MAC protocol based on CSMA/CA avoidance, and compares the impact of OLSR and AODV routing protocols on node communication performance, thereby ensuring the real-time and reliability of AUV multi-node networking communication. In response to the relatively simple and easy-to-learn, good scalability, and resource-saving characteristics of the NS-3.31, a simulation model for underwater electric field communication based on CSMA/CA channels was constructed, and simulation and research on various levels of networks, protocols, etc., were achieved [24; 25]. This article constructs a CSMA/CA underwater electric field communication simulation model with five nodes and verifies the effectiveness of the simulation model through parameters such as packet delivery rate and delay. A computer network is a network where multiple computers are connected through network cards and media, and the machines are equipped with corresponding software protocols. In NS-3.31, the application layer and protocol stack are connected, and the application layer and IP layer are connected through the transport layer. In NS-3.31, the network equipment includes the MAC layer and the physical layer, and the channel is equivalent to the media layer. Among them, hardware includes network nodes, network connection cards, and network connection cables, while software includes TCP/IP network protocol stacks, etc. The CSMA/CA channel network structure constructed in this article includes an application layer, transport layer, network layer, IP layer, link layer, and application layer, achieving the design of the entire multi-node communication simulation process. Thus, the construction of the network simulation environment for nodes, network devices, channels, and applications in NS-3.31 [26] was completed, and the model validation of multi-node network communication in underwater electric field communication was achieved.