adaptive overhead reduction via mewma control charts
In an effort to reduce overhead in proactive protocols, rather than use a global period for transmission of control information, we propose to transmit based on changes in a node's local conditions. For OLSR, a proactive link-state routing protocol, we use a significant change in the number of edges in a node's two-hop neighbourhood and topological graph as indicators of topology change warranting an update. When the associated exponentially weighted moving average (EWMA) charts and multivariate EWMA chart signal out-of-control, a node transmits a HELLO, a topology control (TC), or both HELLO and TC messages. We use ns-2 simulations to compare OLSR to our TS-OLSR, and other variants of OLSR. We find that TS-OLSR obtains a statistically significant reduction in overhead compared to the other protocols while maintaining the packet delivery ratio. The approach is general and may find use in other applications requiring response to changes in local conditions.
ewma charts statistical process control control overhead