A Study on Communication Performance in AIS Network of Inland Rivers

With rapid increasing of ships, the channel load of AIS system in dense navigable water areas also increses rapidly.Time slot conflict in systems, channel congestion, and anomaly communication of AIS network, which cause reduction of reliability for its application, is becoming a hidden hazard of ship navigation safety.In order to accurately and timely reflect the actual situation of communication performance in AIS network, indicators are monitored in real-time based on AIS integrated application platforms.Based on the AIS data of Wuhan section of Yangtze River, the communication performance of AIS network in this water area is evaluated using one week data from five aspects, which are network capacity, network channel load, network throughput, network utilization, and network blocking rate.The tendency and limit state of the communication performance in AIS network is studied by a simulation.The results show that the channel load rate of AIS network in Wuhan section is about 15%, while its throughput is close to 100%, and communication performance is good.If the number of ships increases when the channel load rate reaches 60.5%, communication congestion will be achieved in the AIS network, and the number of ships in 13 motion states are obtained when communication congestion occurs.The results objectively and accurately reflect the communication performance of AIS network in studied area, and can provide technical supports to monitor, manage, and control the AIS system for inland maritime authorities.