A Research On Networking Mechanism Of Ship AIS Self-Organizing Network

With the development of oceanic communication services,the communication capability of the Automatic Identification System(AIS)network on ships cannot meet the demand for short message service cross-regional communication under conditions of no basic communication infrastructure.Therefore,people have added routing protocols to the AIS network to provide cross-network services for short message services.However,there are problems with the current ship AIS self-organizing network,such as routing protocol dependency on basic communication infrastructure,easy failure of edge area routing,and excessive broadcasting of control messages.This thesis focuses on the data link layer and network layer networking mechanisms.In terms of the data link layer networking mechanism,this thesis focuses on the slot resource allocation problem in the channel access scheme,and conducts in-depth research on slot reservation algorithms such as Self-Organizing Time Division Multiple Access(SOTDMA)and Random Time Division Multiple Access(RATDMA),and applies RATDMA to provide channel access services for routing control messages and data messages.For the AIS network access and in-network protocol flow in remote areas without basic communication infrastructure,this thesis designs and implements a channel access protocol.For the slot conflict problem of SOTDMA,this thesis conducts theoretical and experimental analysis using two theoretical models,the binomial distribution and the Poisson distribution.Finally,network simulations show that AIS layer two networking has different networking performance under different scenarios,and network performance is positively correlated with the total number of nodes and reporting rate.In terms of the network layer networking mechanism,this thesis designs and implements an AIS routing scheme based on Greedy Perimeter Stateless Routing(GPSR)and Ad-Hoc On-Demand Distance Vector(AODV)to address the existing narrow communication range and reliance on basic communication infrastructure support issues in the current AIS network.With the GPSR networking mechanism,this thesis designs a method to reduce the greedy forwarding selectable range to optimize edge communication GPSR forwarding operations,which addresses the problem of edge routing failure caused by fast ship movement.For the problem of obtaining destination node location information in the absence of basic communication infrastructure,this thesis proposes an adaptive forwarding strategy for location messages,which effectively reduces the total number of location message transmissions compared to the original forwarding strategy.With AODV networking mechanism,this thesis designs a maximum location distance field-based AODV scheme(LAODV)to reduce the broadcast volume of RREQ control messages and proposes three RREP response measures to accelerate the reply of RREP control messages that reply slowly.Simulation results show that the two networking mechanisms effectively implement AIS layer three networking without affecting AIS identification functionality.In different network scenarios,the GPSR improvement scheme and LAODV scheme have their respective advantages.To improve the research and development efficiency of the networking mechanism,this thesis developed a ship AIS self-organizing network simulation system,including network planning,network simulation,interface display,and database functions,and verified the layer two and layer three networking mechanisms of ship AIS self-organizing network through simulation,demonstrating effective routing services for short message services without affecting AIS identification functionality.