UBC Theses and Dissertations
A cross-layer approach to reducing packet latency in mobile ad hoc networks Gervais-Harreman, Olivier
Mobile Ad Hoc Networks (MANETs) are known for providing connectivity between devices quickly and easily, without requiring an underlying infrastructure. Nevertheless, they are not popular commercially because they cannot effectively support applications that are delay-sensitive. This drawback stems from the fact that most of their routing protocols choose routes according to the shortest-hop criterion. When congestion is present in the network, the shortest path from source to destination is not necessarily the one that minimizes packet latency. To expedite packets to their destination, link-layer information must be available at the routing layer so that the routing protocols can avoid regions that are congested. This thesis characterizes congestion in terms of end-to-end delay, as the sum of expected contention delays at transmitting nodes. By integrating this additive link-layer metric into their decision-making process, existing on-demand routing protocols become better equipped to choose routes that reduce the average end-to-end delay of packets. Simulation results demonstrate that this metric can produce significant gains in end-to-end delay performance for both Dynamic Source Routing (DSR) and Ad Hoc On-Demand Distance Vector (AODV) routing. This increase in performance allows for more user applications to be supported by MANETs, which is sure to drive commercial demand for devices that can connect in this way.