72,562 research outputs found
Plausible Mobility: Inferring Movement from Contacts
We address the difficult question of inferring plausible node mobility based
only on information from wireless contact traces. Working with mobility
information allows richer protocol simulations, particularly in dense networks,
but requires complex set-ups to measure, whereas contact information is easier
to measure but only allows for simplistic simulation models. In a contact trace
a lot of node movement information is irretrievably lost so the original
positions and velocities are in general out of reach. We propose a fast
heuristic algorithm, inspired by dynamic force-based graph drawing, capable of
inferring a plausible movement from any contact trace, and evaluate it on both
synthetic and real-life contact traces. Our results reveal that (i) the quality
of the inferred mobility is directly linked to the precision of the measured
contact trace, and (ii) the simple addition of appropriate anticipation forces
between nodes leads to an accurate inferred mobility.Comment: 8 pages, 8 figures, 1 tabl
Exploring the use of mobile sensors for noise and black carbon measurements in an urban environment
Mobile measurements have been collected on a bicycle equipped with a global positioning system (GPS) in a few connecting streets in Gent (Belgium). The 1-s sound pressure levels and 1-s black carbon concentrations were measured. In addition, 5 continuous monitoring fixed stations connected to building facades were used. Different processing methods are compared, based on different temporal and spatial weighting aggregations. The possibility to take profit of the fixed stations to refine estimations is tested, according to the noise levels collected at fixed stations and the distance between mobile and fixed sensors. In a last step, route selection based on travel distance, noise levels and black-carbon measurements is explored based on the data obtained
Update Delay: A new Information-Centric Metric for a Combined Communication and Application Level Reliability Evaluation of CAM based Safety Applications
Standard network metrics, such as throughput, latency and reception probability, are the most popular performance indicators used in the literature to describe and compare communication protocol variations. However, these “traditional” network-centric PI are not adapted to the distributed, information-centric nature of the beaconing communication pattern, nor do they cover application level reliability or freshness of information.
In this paper, we introduce a more suitable metric called Update Delay, represented as a Complementary Cumulative Distribution Function (CCDF). We will show how this single Update Delay performance indicator can be an optimal representation of the freshness and reliability of the information about a certain transmitter, i.e. awareness about vehicles and their current state in the vicinity. This paper extends on the methodological aspects of the approach, as well as introduces several concrete examples
Performance and configuration of link adaptation algorithms with mobile speed
Link Adaptation is an adaptive radio link technique that selects a transport mode, from a set of predefined modes of varying robustness, depending on the channel quality conditions and dynamics. Previous work has shown the need to adapt the configuration of the Link Adaptation algorithm to certain operating conditions such as the system load. Since the channel quality dynamics are also influenced by the user speed, this paper investigates the impact of the mobile speed on the performance and configuration of Link Adaptation algorithm
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