Current Issue : January - March Volume : 2017 Issue Number : 1 Articles : 5 Articles
Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) communication systems, known as V2X technologies, have\nincreasingly attracted attention in current research on road safety and traffic ergonomics. The performance evaluation of these\ncommunication systems is an important step before their potential integration and use in real systems. V2X communications are\nbased on the IEEE 802.11p standard also known asWireless Access in Vehicular Environment (WAVE). V2X can affect human life;\ntherefore a deep study related to V2X performance evaluation should be done in order to be sure about the systemreliability. In this\ncontext, we have elaborated a deep study related to the effect of transmission range on V2X communications by considering the\nterminal mobility. First, we have evaluated the performance of the PHY layer on the IEEE 802.11p using simulation. Secondly, we\nhave conducted real casemeasurements using the Arada LocoMate Transmission system.Theobtained results shows the necessity to\noptimize the quality of transmission in V2X communications. Consequently, we propose in this paper a new comb-pilot technique\nto enhance the quality of Orthogonal Frequency Division Multiplexing (OFDM) transmission. Our proposal consists in two new\nuses of the pilot subcarrier estimation technique in order to decrease the elevated bit error rate (BER). The quality of transmission\n(QoT) is first evaluated relating to the pilot symbol rearranged positions. Second, we proposed to optimize the QoT by adding two\nsupplementary pilot symbols as it can offer better channel estimation results. Based on the performance evaluation of our proposal,\nit is confirmed that both of rearrangement and the adding of the pilot patterns lead to performance enhancement compared to\nbaseline model (standardized one)....
Automobiles automated perpendicular parking using Artificial Potential Field (APF) is discussed in this paper. The Unmanned\nGround Vehicle (UGV) used for carrying out experiments is introduced first; UGV configuration, kinematics, and motion\ncontroller are included. Based on discretized form of the parking space, the APF is generated. Holonomic path for the vehicle\nparking is found first; path modification to satisfy minimum turning-radius constraint is performed based on Reeds-Shepp curve\nconnections. Optimization efforts are included to remove extra maneuvers and to reduce length of the path. Afterwards waypoints\nare generated as reference for the vehicle to track. Perpendicular parking tests with several different start configurations are\ndemonstrated; based on the test results the automated parking framework proposed in this paper is considered to be effective....
Content dissemination over vehicular networks is a critical challenge due to its high intermittent connectivity. However,\ncontent cache and retrieval by exploiting the information-centric networking (ICN) paradigm did not get much\nattention. In this paper, in order to improve the efficiency of content retrieval, we propose a novel popularity-aware\ncontent caching and retrieving strategy in VANETs named P-CCR, which innovatively considers the ICN perspective into\nvehicles mobility and vehicular wireless communication in highway scenarios. At the same time, it supports to\nindependently switch the retrieval modes between vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I)\naccording to the popularity of contents. Most notably, an actively caching mechanism is proposed in P-CCR,\nwhich can be triggered to inform surrounding volunteer vehicles to cache contents requested in a short time.\nExtensive simulations highlight that P-CCR significantly reduces RTT value and the amount of interest packets, which\ncan lighten network loads and avoid wasting resources....
Vehicular ad hoc networks have been developed in consideration of advancing driving safety. In driving-safety\napplications, rapid dissemination of warning messages is highly demanded to avoid accidents involving incoming\nvehicles. Broadcast transmission is considered the most appropriate technique to spread warning messages because\nit can simultaneously reach all neighboring nodes within a transmission range using only a brief wireless media\naccess. However, blindly broadcasting redundant messages may severely overcrowd wireless media channels and\nprovoke transmission collisions; this is known as the broadcast storm problem. In order to reduce broadcast\nredundancy, broadcasting must be intelligently controlled. Simultaneously, an intelligent broadcast scheme should\naim to reduce the number of hops needed to arrive at a destination, to achieve smaller propagation delay. In this\npaper, we observed the behavior of a few broadcast schemes and found that their performances can be explained as\nlimiting a space to control the number of contentions in broadcasting. From the observation, we propose a limited\narea-based (LAB) scheme to achieve a shorter propagation time as well as a smaller number of redundant broadcast\nmessages. The proposed scheme can maintain a proper collision rate to obtain a faster propagation time by adjusting\nthe size of an area in which broadcasting nodes belong. Performance evaluation results from simulation show that the\nproposed scheme is feasible and reasonable....
Traffic accident involving vehicles is one of the most serious problems in the transportation system nowadays. How to detect\ndangerous steering and then alarm drivers in real time is a problem. What is more, walking while using smartphones makes\npedestrian more susceptible to various risks. Although dedicated short range communication (DSRC) provides the way for safety\ncommunications, most of vehicles have not been deployed with DSRC components. Even worse, DSRC is not supported by the\nsmartphones for vehicle-to-pedestrian (V2P) communication. In this paper, a smartphone-based framework named SenSafe is\ndeveloped to improve the traffic safety. SenSafe is a framework which only utilizes the smartphone to sense the surrounding\nevents and provides alerts to drivers. Smartphone-based driving behaviors detection mechanism is developed inside the framework\nto discover various steering behaviors. Besides, the Wi-Fi association and authentication overhead is reduced to broadcast the\ncompressed sensing data using the Wi-Fi beacon to inform the drivers of the surroundings. Furthermore, a collision estimation\nalgorithm is designed to issue appropriate warnings. Finally, an Android-based implementation of SenSafe framework has been\nachieved to demonstrate the application reliability in real environments....
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