Modeling and Analysis of Bulk Bundle Release Schemes in Two-Hop Vehicular DTNs

The use of vehicular infrastructure to establish connectivity between isolated stationary Information Relay Stations is an appealing application of Terrestrial Delay-Tolerant Networking. A source opportunistically releases data bundles to vehicles that randomly enter its range. In turn, those vehicles store the received bundles, carry and deliver them to their intended destination. It follows that a contemporaneous source- destination end-to-end path does not exist. Consequently, bundles experience longer queueing periods at the source. Under such circumstances, the end-to-end bundle delivery delays become several orders of magnitude higher than those experienced in traditional wireless networks. In this context, bundle delivery delay minimization emerges as a challenging problem that has not been adequately addressed in the open literature. This paper proposes a simple Probabilistic Bundle Relay Strategy with Bulk Bundle Release (PBRS-BBR) that aims at minimizing the average end-to-end bundle delivery delay while capturing the essence of vehicular delay-tolerant networking in that it revolves around minimal network information knowledge. A queueing model is formulated to represent stationary sources operating under PBRS-BBR. This model is mathematically analyzed and validated through extensive simulations that gauge its merit.