Indeed, routes changes due to dynamic and mobility of nodes result in unsteady packet delivery delays and packet losses, which should not be considered as congestion control faults. Ĭongestion control is a challenging subject in mobile ad hoc networks, mainly because of the shared nature of the wireless multihop channel and the frequent changes of the network topology. Indeed, the wireless channel can be occupied by competitive nodes for many reasons (collisions, interferences, insufficient signal strength, duration of the transmission sequence, etc.). Another important constraint in the multi-hop inter-vehicular communications is the limited bandwidth within a such environment. In addition, in 50% of all occurrences, the maximum potential communication duration is 1 second in 90% of the occurrences, the upper boundary for the communication time is 5 s. They carried out simulations and analysis showing that the average number of potential communication neighbors is optimally four. evaluate the neighboring nodes configuration of vehicular networks within a four highway lanes context (two lanes for each direction). Indeed, within VANET networks, nodes are characterized by high dynamic and mobility, in addition to the high rate of topology changes and density variability. In addition to the challenging characteristics of MANETs (such as lack of established infrastructure, wireless links, multi-hop broadcast communications), VANET brings new challenges to realize safe communication architecture within such environment. Vehicular ad hoc networks (VANET) are a type of MANETs used for communication among vehicles and between vehicles and roadside equipment (cf. Considering the context of high reliability and real-time response required for intervehicular communications (including emergency breaking notification for example), we propose a complete validation method of our congestion control algorithms, taking into account reliability, temporal, and operational aspects. Messages priorities are dynamically evaluated according to their types, the network context, and the neighboring nodes configuration. In this context, we present in this paper a cooperative and fully distributed congestion control approach, based on dynamic scheduling and transmission of priority-based messages, to ensure reliable and safe communication architecture within VANET. Ensuring congestion control within vehicular ad hoc networks faces special challenges, due to the specificities of such environment (High mobility of nodes, high rate of topology changes, high variability in nodes density and neighborhood configuration, broadcast/geocast communication nature, etc.). Appropriate congestion control mechanisms are essential to provide effcient operation of a network. The main objective of congestion control is to best exploit the available network resources while preventing sustained overloads of network nodes and links.
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