The impact of delay in dominating set and neighbor elimination based broadcasting in ad hoc networks

In a broadcasting task, a source sends a message to all the nodes of a network. There exist methods for flooding a network intelligently and for scheduling node activities. Dominating sets and neighbor elimination based broadcasting is currently the most efficient broadcasting scheme in terms of the number of retransmitted messages to complete a broadcast. It provides basis for defining other broadcasting protocols by changing the definition of the delay (timeout) function used to decide how long a dominating node should wait before making a retransmission. In this article, we propose thirteen such variants. They are all reliable, meaning that all the nodes connected to a source will receive the message, assuming an ideal MAC layer. Eight of them are hexagonal based; four are distance-based, giving priority to the neighbors that are further or nearer from the retransmitting node; and one is using a random timeout. Beyond these variants, we propose three different ways to update the timeout values during a broadcasting process. Our experimental data shows that the updating process of the timeout values has no significant impact compared to the selected timeout function. From the thirteen variants we deliberately proposed some worst-case timeout functions to see its impact in the broadcasting process. We confirm by our experimental data that indeed the selected timeout function has an impact in the broadcasting process. Although our experimental data shows that the new further distance-based scheme outperforms almost all schemes in terms of number of messages to complete a broadcast, it also shows that a random function (the way IEEE 802.11 works) is a very good choice.