Virtual data mules for data collection in road-side sensor networks

OMS: Opportunistic mules for short latency data collection in smart cities

“…Moreover, they attribute the mule role to vehicles with fixed trajectories and periodic schedule leading to an increased data delivery delay. In this regard, the works presented in previous studies are basically relevant to the research described here as they involve sensors deployed at fixed geographical positions. Lan and Wu, studied the feasibility of using public transport as DMs to collect information about road traffic collected by stationary sensors.…”

“…However, the issue of collecting the data from the huge amount of sensors and actuators spread across streets is still considered as the main challenge for smart city realization. In fact, the complexity of the urban environment can cause network fragmentation due to forcefully sparse node deployments or unpredictable dynamics in wireless link availability . Even if cellular communications have been suggested as an alternative solution, it could be very expensive because of the need of a permanent infrastructure to be built to cover all the nodes.…”

“…One effective, economical, and suitable way to deliver sensor data to the central controller is to exploit mobile elements (MEs) that may be robots or vehicles. In fact, while moving, MEs can download sensors data once they are within their communication range . This approach, well known as data mule (DM) approach, is proved to be effective in energy economy as well as energy consumption balancing, which are considered as the main issues in traditional WSN multi‐hop forwarding strategies.…”

“…Several works deal with urban data collection using vehicles as DMs or mobile sinks. In Borsetti et al, the DM concept is adapted to urban mobility by handing over the mule role to a better candidate, when the trajectory of the vehicle acting as DM does not fit the planned trajectory. The DM concept is then extended to a more realistic entity called “oblivious data mules” where taxicabs are used to deliver the data of a smart city to the urban monitoring center.…”

Reducing message delay with the general Message Ferry Route (MFR*) problem

“…Let's consider the following real life scenario where mobile wireless ad hoc network are applied: Scenario 1: To provide Internet services in rural areas, vehicles such as buses can be deployed as message ferries, as proposed in the Data MULEs scheme [5], [14], [9] and the DakNet project [7]. Such vehicles, as message ferries, may stop at a series of predetermined locations (such as bus stops) to transmit and receive messages.…”