Design And Realize Routing Algorithm And Buffer Management Policy Based On Urban Public Transport System

Wireless public transport network, as an important carrier of intelligent public transport system, has aroused wide attention from researchers. The studies of traditional vehicle networks did not consider that buses, light rail vehicles and subways move regularity, periodicity, immobility and high dynamic. Therefore, the previous routing algorithms and buffer management policies can not fit the public transport network. In order to meet people’s urgent demand for information-based public transport system, it is necessary to present routing algorithm and buffer management policy for public transport network, and make a further study. Making full use of public transport network’s characteristics is the crux of improve the performance of routing algorithm and buffer management policy.According to the characteristics of public transport network, this article presents Bus Line-based Routing (BLR). This routing algorithm is based on the shortest distance between bus lines to make routing decisions. Comparing to traditional routing algorithms, its routing strategy is more targeted. In forwarding process, set a transmission queue to forward messages selectively when two nodes make a communication. Then, in order to further limit the number of copies and reduce resource consumption in the network, this article presents Copy Constrained Bus Line-based Routing (CCBLR).In public transport network, bus has a high speed, which lead to the connection between buses has a limited duration, so buses should try to ensure a good performance of packet transmission in a short time. Therefore, this article presents Bus Line-based Buffer Management (BLBM), this buffer management policy is also based on the shortest distance between bus lines to manage packets. According to real-life scenarios, this article set up simulation scenarios and simulates the performance of routing algorithm and buffer management policy in these scenarios. Experimental results show that BLR and CCBLR have a better performance in terms of delivery rate and the number of copies than traditional routing algorithms. BLBM has a better performance in terms of delay time and hop count than FIFO, Random and Priority.