Description

Existing on-demand ad hoc network routing protocols continue using a route until a link breaks. During the route reconstruction, packets can be dropped, which will cause significant throughput degradation. In this thesis, we add a link breakage prediction algorithm to one on-demand routing protocol: the Dynamic Source Routing (DSR) protocol. The mobile node that implements the prediction algorithm uses signal power strength from the received packets to predict the link breakage time, and sends a warning to the source node of the packet if the link is soon-to-be-broken. The source node can perform a pro-active route rebuild to avoid disconnection. Experiments demonstrate that adding link breakage prediction to DSR, even considering the increased number of control messages, can significantly reduce the total number of dropped data packets due to link breakage by reducing the number of broken links. We believe that TCP can potentially benefit well from the pro-active route maintenance to increase throughput, which is affected by broken links. We also propose a modification plan for AODV and make recommendations about further improvement on DSR based on the link breakage prediction.