Research On Opportunistic Network Routing Strategy For Maritime Volunteer Ships

The voluntary marine observation ship is responsible for the collection of ocean observation data,and delivers the data in two ways: satellite transmission and land-to-shore transmission.Satellite transmission can quickly bring data to shore,but the communication cost is high.It is only suitable for the transmission of marine emergency data.For the high-density and massive non-emergency data collected by the observation ship,it can only be delivered after the ship reaches the shore.As a result,the data cannot be transmitted to the shore-based control center quickly,timely,and accurately.Therefore,this paper applies the opportunistic network to the data communication scenario of maritime volunteer ships,and uses the "storagecarry-forward" mode to achieve high-density and efficient transmission of massive observation data.This paper proposes routing protocols with high reliability and low overhead.The specific contributions are as follows:(1)A dynamic distribution routing protocol based on probability for maritime opportunistic networks is proposed.A large number of research results indicate that the ship’s trajectory shows a certain regularity.Based on this feature,this protocol introduces an encounter probability mechanism in routing decision-making,which dynamically adjusts the encounter probability through the frequency of encounters between nodes.The multi-copy message distribution strategy is used in the protocol to allow nodes with greater delivery probability to carry more copies.At the same time,the congestion avoidance strategy is added to reduce invalid forwarding.The simulation shows that the protocol can reduce the routing overhead while increasing the delivery rate.(2)An opportunistic routing protocol based on location prediction is proposed.The ship’s movement status is affected by speed,heading,etc.This protocol trains the ship’s movement trajectory model in the long short-term memory(LSTM)network by selecting these movement features as a sample feature set,and uses the output correlation of the LSTM network to predict the location of the ship.When making routing decisions,the future position of the ship and the number of copies of its own messages are comprehensively considered,and the number of copies forwarded is calculated flexibly.In this way,the selection of relay nodes and the distribution of copies are more reasonable.The simulation results show that this protocol has high reliability and can effectively reduce routing overhead.(3)In order to verify the practicability of the opportunistic routing protocol,the real maritime environment and ship communication conditions are reduced in proportion.An opportunistic routing protocol verification platform for Internet of Vessels based on the Android system is designed.The platform uses the encounter between Android devices to simulate the encounter of ships,Bluetooth communication to simulate shortwave communication between ships at sea,and the PC terminal in the laboratory environment to simulate the shore-based control center to deliver the generated messages.Dynamic distribution routing protocol based on probability is deployed to the platform for comprehensive verification.The verification results show that the protocol performs well in the experimental environment,can achieve reliable message transmission,and has certain practical value.The content studied in this paper is of great significance for solving the problem of Internet of Vessels data transmission.Simulation experiments show that the proposed protocols can effectively reduce transmission overhead while achieving reliable message transmission,and have certain practical value.