Modeling and Delay Analysis of Intermittently Connected Roadside Communication Networks

• Published in: IEEE transactions on vehicular technology 2012-07, Vol.61 (6), p.2698-2706
• Main Authors: Khabbaz, M. J., Fawaz, W. F., Assi, C. M.
• Format: Article
• Language: English
• Subjects: Analytical models; Applied sciences; Bundle; Bundles; Delay; disruption tolerant networking (DTN); Exact sciences and technology; Interconnected networks; intermittently connected network (ICN); Internet; Mathematical model; Minimization; modelling; Networks; Networks and services in france and abroad; Operation, maintenance, reliability; performance evaluation; Queueing analysis; Queues; Relays; Roadsides; Studies; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Teleprocessing networks. Isdn; Teletraffic; Transit; Transmission and modulation (techniques and equipments); Vehicles; vehicular
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2012.2200001

Vehicular networks outline a challenging terrestrial application of the emerging delay-tolerant networking (DTN) paradigm where wireless links experience frequent disruptions. Thus, continuous end-to-end paths are unguaranteed. Under such conditions, mobile vehicles present opportunistic relaying capabilities that promote network connectivity, particularly between stationary and isolated roadside units. In this context, we investigate a challenging information-delivery-delay minimization problem. Information is encapsulated into bundles buffered at the source, and vehicles opportunistically transport them to the destination. Consequently, bundles undergo both queueing and transit delays. We propose a probabilistic bundle release scheme (PBRS) under which a roadside unit performs typical Internet-like forwarding where a single bundle is only released to an arriving relatively high-speed vehicle. This ensures a minimized bundle transit. In contrast, under a greedy bundle release scheme (GBRS), a bundle is released to any arriving vehicle, regardless of its speed. Two queueing models are developed to characterize a roadside unit and evaluate its performance under both schemes. A simulation framework is set up to validate these models. Results indicate the inefficiency of the typical Internet packet-like release mechanism as it incurs excessive bundle queueing delays. A bulk bundle release (BBR) extension is proposed as an effective solution. We show that GBRS-BBR outperforms PBRS-BBR.