Current Issue

Mobile Communication Networks

      Vehicle-to-vehicle (V2V) communication, also known as inter-vehicular communication (IVC), enables vehicles to exchange messages and self-organize into dynamic vehicular ad hoc networks(VANETs). These features will allow the deployment of a broad range of intelligent transportation applications. For example, [7] proposes a wireless local danger warning (WILLWARN) system, which relies on the onboard vehicle-hazard detection and V2V communications, and is focused on low penetration levels in rural traffic by a new message-management strategy;[9] reports the significant safety improvement by combining V2V communications with internal and external sensing devices; and a GPS-complementary V2V-assisted localization technique is presented in [2].
      To cope with the emerging communication needs in various applications, several V2V communication frameworks have also been developed. In [3], such a framework is established for the cooperativeactive safety system (CASS) whose operation is based on the dissemination of each vehicle’s state information through a wireless network. [8]further realizes the needs of adaptively accounting for the distinct characteristics in terms of the generated network traffic corresponding to different applications. The authors then propose a V2V architecture that can adapt its functionalities to efficiently serve different applications. In a safety system based on neighboring vehicle monitoring, [1] proposes a new type of query in order tooptimize the usage of the wireless network bandwidth, computational cost, and local storage while preserving information on the continuous movement of vehicles within the broadcast range of a vehicle.
       Unlike wired networks, where communication links are inherently stable, in wirelessnetworks such as the VANET, the lifetime of a link is a random variable whose probability distribution depends on mobility, transmission range, and various impairments of radio communications. Because of the very dynamic nature of VANETs and the short transmission range mandated by the Federal Communications Commission (FCC), individual communication links come into existence and vanish unpredictably. [11]investigates the probability distribution of the lifetime of individual links in a VANET under the combined assumptions of realistic radio transmission and probability distribution models ofintervehicle headway distance.[5]also realizes that a direct connectivity between equipped vehicles in one direction is rarely possible at the current stage of ITS development. An alternative mode is investigated in which messages are stored by relay vehicles traveling in the opposite direction and forwarded to vehicles in the original direction at a later time. By means of integrated microscopic simulations ofcommunication and bidirectional traffic flows, the theoretical expectation for multilane roadways is validated and analyzed.
      Development of real-time applications based on V2V communications requires a reasonable assurance of the network performance, such as the packet loss rate and end-to-end latency, both of which are strongly dependent on the wireless propagation properties. To this end, [4] improves on simpler propagationmodels for simulations by augmenting ray-tracing-derived models of propagation, [10] applies an adaptive circular array antenna to a direct sequence spread spectrum (DSSS) V2V system under shadowing environment, and [6] investigates the non-line-of-sight (NLoS) reception on a 5.9GHz inter-vehicle communication channel.
      The significant social and economic impacts of road congestion and traffic-related pollution have been widely recognized worldwide. V2V communication consists of one pivotal tool in improving the monitoring, distribution, and processing of traffic information for safety and efficiency.

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