DC4LED: A Hierarchical VDTN Routing for Data Collection in Smart Cities

In smart cities, the mobility of vehicles can be used to collect data produced by connected objects and to deliver them to several applications which are delay tolerant. The Vehicular Delay Tolerant Networks (VDTN) can be utilized for such services. This paper introduces DC4LED (Data Collection for Low Energy Devices): a hierarchical VDTN routing which takes advantage of the specific mobility patterns of the various type of vehicles. It provides a low-cost delivery service for applications that need to gather data produced from the field. The idea is to propose a simple routing scheme where cars, taxis, and buses route data hierarchically in a store carry-forward mechanism to any of the several available Internet Point-of-Presences in the city. This paper aims to explore the possibility of implementing a very simple mechanism for very simple services, as opposed to utilizing complex VDTN mechanisms proposed in the literature. Our simulations compare the performance of DC4LED routing with two legacy VDTN routing schemes which represent the extreme ends of VDTN routing spectrum: First-contact and Epidemic routing. It show that DC4LED has much lower network overhead in comparison with the two legacy routing schemes, which is advantageous for its implementation scalability. The DC4LED also maintains comparable data delivery probability and latency to Epidemic routing.