Enhanced Delivery in Disruption Tolerant Networks using Advantaged Nodes with Directional Antenna Capability

Disruption tolerant networks are designed to deal with the limited connectivity among mobile nodes due to mobility, short range radios or terrain obstacles. Several routing schemes have been proposed for DTNs. These routing schemes rely on the node mobility to deliver packets amidst frequent and extended network partitions using a store-and-forward approach. Recently, researchers have proposed that special stationary nodes are deployed to enhance contact opportunities and hence improve the delivery performance. In this paper, we propose adding directional antenna capability to such advantaged nodes to further enhance the delivery performance. We evaluate the extent of the improved delivery performance when these advantaged nodes are deployed in grid-like or random manners. Unlike the earlier work, in our evaluation, we do not assume that one can learn the mobility patterns of the moving nodes since such learning is not feasible in military and emergency disaster scenarios. Our results indicate that an additional 14% (10%) improvement in delivery ratio can be achieved with grid-like (random) deployments. The improvement in average delivery latency is about 5%.