Traffic systems recovery from complete congestion by the targeted dropping of packets

Abstract

Relieving complete congestion in a traffic system is an important problem. We propose a strategy to realize this, in which the packets on nodes shared by many shortest paths are dropped preferentially. A simple scale-free network is chosen to demonstrate the importance of the degree heterogeneity to the congestion problem, though this network structure cannot mimic a real traffic network. Two traffic models are simulated: in one of which, all the nodes are identical, and in the other, the delivering capacity and storing ability for each node are both proportional to its degree. Both models can give a phase transition between free-flow and congested states, while the latter model has significant strong transportation performance (a larger critical value of the packet generation rate). The strategy of preferentially dropping packets on nodes shared by many shortest paths, as proposed in this paper, can realize remarkably better transportation performance measured by the fraction of congested nodes and the average arrival rate compared with the random packet dropping strategy in the literature.