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Traffic congestion is a serious problem in urban areas of many countries due to the increasing amount of vehicles on surface streets and accompanies fuel-wasting and air-pollution. This problem can be alleviated by adopting a ride-sharing service. The main idea of ride-sharing service is to collect travelers whose travel destinations are nearby into one vehicle. In doing so, we can reduce the amount...
Because of shortage of raw materials, the energy-saving issues become popular in Vehicular Ad-hoc Networks (VANETs). A VANET is formed by traveling vehicles with communicating capability and thus it brings various applications. Navigation system is one of important applications in VANETs. The traditional navigation system usually plans a shortest path for users according to geographic maps but the...
LTE is currently considered by many wireless operators as their next generation technology. During a transition phase, LTE will be deployed as an overlay on an existing wireless technology, which acts as an underlay. It is expected that initial LTE deployment will be patchy with coverage holes. In this paper, we model and analyze the impact of dual-technology deployment on signaling load at critical...
This paper presents a connectivity improvement strategy for sparse free-flow Vehicular Ad hoc Networks(VANETs) subject to channel randomness. We first model the connectivity of VANETs in the form of mean broadcast percolation distance based on the equivalent M/G/∞ queue theory. Thereafter, to address the problem of poor connectivity in sparse VANETs, a distributed connectivity improvement strategy...
The increased traffic density in urban areas should be handled by a robust collision avoidance and traffic control system that is based on decentralized inter-vehicle communication. In such a special ad hoc network traditional routing protocols cannot cope with the high mobility and low link reliability, while flooding based approaches consume too many resources. Our proposed solution, Carefully Localized...
Cooperative vehicle safety (CVS) systems rely on vehicular ad-hoc networks operating in broadcast mode to deliver vehicle tracking and safety information to neighboring cars. This information is used to enable collision avoidance and warning systems. One of the main challenges of the eventual large scale deployment of such systems is network congestion, which could critically degrade the quality of...
Video and image communications can assist in highway traffic control, accident avoidance and management as well as road congestion control and coordination. This paper studies video streaming over wireless medium among a cluster of vehicles in an ad-hoc network. Through intense tradeoff study, we investigate the issues encountered in building a robust system that would allow automobiles to effectively...
Spatial processing techniques such as Adaptive Array Antenna (AAA) and Multi-Input-Multi-Output (MIMO) are being considered for use in the next generation mobile cellular systems. In order to accurately estimate the performance of these spatial processing techniques in wide-band mobile communications, we need a time-spatial path model that can present the delay profile and the spatial arrival angular...
In VANETs(Vehicular Ad Hoc Networks), moving from one RSU's coverage region to another will bring reauthentication in the new security domain, which can be named security handover problem. In this paper, based on mobility predictability, we propose a novel anonymous communication scheme called SCPT to address the security handover problem. It uses hash chain for vehicle's anonymous authentication...
The Intelligent Transportation Systems (ITS) currently attract a lot of attention. Many simulators and some testbeds have been proposed to validate new ideas and to guide new theoretical developments. Yet, to this date, simulator tools and testbeds evolve in disjoint research work. We developed Airplug-ns, an open source simulation environment, as a step towards bridging this gap. This environment...
The vehicular ad hoc network (VANET) has attracted a lot of interest recently. However, traditional VANET is just an instantiation of MANET in which nodes are treated equally for data delivery. We first analyze the unique features of urban VANET that vehicles have different types, and move as clusters due to the influence of traffic lights. Then a two tier architecture called Mobile Infrastructure...
Improving the safety of vulnerable road users is an international demand because still thousands of pedestrians and cyclists are injured or killed in accidents with cars, trucks and busses. Car manufacturers and several research groups work on different solutions to avoid accidents with the help of sensor based systems. Moreover, research is done in radio communication based collision avoidance systems...
This paper proposes a novel method for detecting traffic congestions, qualifying and quantifying congestion levels using mobile phones as traffic probes. The system provides a robust mechanism for granularly comparing the seriousness of different congested areas. Congested areas are detected in a detailed manner by which exact congested positions are reported. Moreover, congestions can be detected...
A novel concept of portable charging station networks to serve Electric Vehicles is described. An optimum charging station deployment method is explained, and its performance has been simulated for single highway, two intersecting highways, and Manhattan-like grid traffic models. Outage probability and service waiting delay performances are evaluated. Impact of the number PCSs and the ratio of EVs...
The integration of mobile relays in cellular networks has been recently envisioned as a way of increasing system capacity, coverage and reducing communication energy consumption. In we studied how store carry and forward (SCF) relaying within the cell can be utilized as an underlay message forwarding mechanism to achieve system wide energy savings. In this paper, by deriving optimal routing policies...
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