Research On Cooperative Adaptive TDMA Protocol Of Underwater Cluster

With the rapid development of marine science and technology,the autonomous underwater vehicle and underwater acoustic communication network has been developed rapidly.The underwater vehicle is represented by AUV towards the research and development of clustering and intelligence.The Media Access Control(MAC)protocol,as one of the key technologies in underwater acoustic networks,has been continuously studied to ensure reliable communication between nodes.TDMA protocol,as a MAC protocol,has the advantage of low communication data collision rate and is widely used in the field of network communication.However,underwater acoustic channels have the characteristics of large propagation delay and complexity,which makes underwater TDMA protocol have greater network delay compared with land.In this paper,we design an adaptive TDMA protocol for efficient communication based on TDMA protocol for mobile network scenarios under small-scale nodes without localization,which can effectively solve the problem of large transmission delay of TDMA protocol in communication networks and improve the network protocol performance.The research work and innovation points of this paper are as follows:1.In order to improve the problems of long idle waiting time of nodes,insufficient channel utilization and inflexible scenario application in the traditional TDMA protocol,the adaptive TDMA protocol is proposed.This protocol can reduce data transmission collisions by adaptively adjusting the idle time slots of each node without reducing protocol efficiency.The adaptive TDMA protocol consists of two main parts,first predicting the idle time slots for future cycles using LSTM neural networks,and then adjusting the predicted idle time slots using an adaptive adjustment algorithm.The protocol shortens the operation cycle with lower data collision rate,improves the protocol efficiency,and maintains good performance in the case of node location movement and data transmission delay variation.2.Simulate and verify the proposed adaptive TDMA protocol in the set marine environment,and compare it with existing MAC protocols.Simulation results show that the adaptive TDMA protocol proposed in this paper has higher network throughput,smaller end-to-end delay and significantly improved network performance compared with TDMA,fixed time slot TDMA and dichotomous TDMA protocols with low packet loss rate.A dynamic training method for the prediction model is proposed to improve the performance of the prediction model and network protocol,and increase the applicability of the protocol,in response to the situation where the performance of the adaptive TDMA protocol prediction model decreases and leads to high data collision rates when each node is in fast motion mode.Considering the changes in the number of nodes in the actual application scenario,the corresponding network protocols for node joining,node withdrawal and node failure are proposed to enhance the applicability and flexibility of the adaptive TDMA protocol.3.Design a set of mobile small-scale grouping motion communication visualization software interface based on underwater acoustic communication using QT platform to realize real-time motion display of mobile nodes.The software functions include random selection of different communication protocols,motion modes,and node joining or exiting,and realtime display of protocol performance,packet sending and receiving status,and other information.Finally,the software system was successfully tested,verifying the effectiveness and applicability of the adaptive TDMA protocol designed in this paper.