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—Increasingly ubiquitous communication networks and connectivity via portable devices have engendered a host of applications in which sources, for example people and environmental sensors, send updates of their status to interested recipients. These applications desire status updates at the recipients to be as timely as possible; however, this is typically(More)
Anytime, anywhere network connectivity, together with portable sensing and computing devices have led to applications in which sources, for example people or environmental sensors, send updates of their status, for example location, to interested recipients, say a location service. These applications desire status updates at the recipients to be as timely(More)
In this paper we present empirical results from a study examining the effects of antenna diversity and placement on vehicle-to-vehicle link performance in vehicular ad hoc networks. The experiments use roof- and in-vehicle mounted omni-directional antennas and IEEE 802.11a radios operating in the 5 GHz band, which is of interest for planned inter-vehicular(More)
Emerging applications rely on wireless broadcast to disseminate time-critical information. For example, vehicular networks may exchange vehicle position and velocity information to enable safety applications. The number of nodes in one-hop communication range in such networks can be very large, leading to congestion and undesirable levels of packet(More)
We examine multiple independent sources providing status updates to a monitor through a first-come-first-served M/M/1 queue. We formulate a status-age timeliness metric and find the region of feasible average status ages for a pair of updating sources. In the presence of interfering traffic with a given offered load, we show the existence of an optimal rate(More)
This paper describes the architecture and design of ParkNet, a mobile sensor network consisting of vehicles, which collects and disseminates real-time information about the availability of parking spaces in urban areas. We outline the broad challenges in real-time data collection and consumption by a mobile sensor network, as well as the design issues(More)
Experimentation with large mobile networks is notoriously tedious and expensive. We present the architecture and work-in-progress implementation of the m-ORBIT testbed, a mobility emulator using spatial switching, which facilitates mobile system experiments with 802.11a/b/g wireless network interfaces. The emulator does not require any physically moving(More)
To evaluate routing protocols on a controlled indoor wireless testbed, the radio range must be compressed so that larger multi-hop topologies can be mapped into a laboratory-size area. We propose noise injection as a more flexible option than hardware attenuation and consider methods for mapping real world wireless network topologies onto the testbed. Our(More)
—This work is motivated by network applications that require nodes to disseminate their state to others. In particular, vehicular nodes will host applications that periodically disseminate time-critical state across the network to help improve on-road safety. In this work, we want to minimize the average age of state information that a node observes from(More)
—Antenna diversity is a well-known technique used to improve the quality and reliability of a wireless link. In vehicular networks, a different approach to antenna diversity is needed due to their unique channel characteristics. However, this issue has not been actively researched, especially for the positioning of antennas. In this paper, we highlight the(More)