Search

In the present paper, we study the evolution of an overloaded cyclic polling model that starts empty. Exploiting a connection with multitype branching processes, we derive fluid asymptotics for the joint queue length process. Under passage to the fluid dynamics, the server switches between the queues infinitely many times in any finite time interval causing frequent oscillatory behavior of the fluid limit in the neighborhood of zero. Moreover, the fluid limit is random. Additionally, we suggest a method that establishes finiteness of moments of the busy period in an M/G/1 queue., Comment: 36 pages, 2 pictures

In this paper, we consider retransmission strategies for centralized cyclic polling-based systems over wireless channels subject to external interference. The considered strategies differ in the time when retransmissions for one particular node are carried out, and in the number of retransmissions that can be carried out for one node. We show experimentally and by simulation that two related strategies introduced in this paper, called the queueing-based strategies, significantly outperform the traditional strategy (in which all admissible trials towards one node are carried out subsequently) in terms of the average number of nodes that cannot be successfully served in a cycle. These performance gains are achieved without increasing the average total transmission effort.