دانلود رایگان مقاله پروتکل های پیش بینی برای شبکه های ادهاک خودرویی

ABSTRACT

The high mobility of vehicles as a major characteristic of Vehicular Ad Hoc Networks (VANETs) affects vividly the dynamic nature of the networks and results in additional overhead in terms of extra messages and time delay. The future movements of the vehicles are usually predictable. The predictability of the vehicles future movements is a result of the traffic conditions, the urban layout, and the driving requirements to observe the traffic constrains. Hence, predicting these future movements could play a considerable role for both building reliable vehicular communication protocols and solving several issues of intelligent transportation systems. In the literature, numerous prediction-based protocols are presented for VANETs. Therefore, this paper follows the guidelines of systematic literature reviews to provide a premier and unbiased survey of the existing prediction-based protocols and develop novel taxonomies of those protocols based on their main prediction applications and objectives. A discussion on each category of both taxonomies is presented, with a focus on the requirements, constrains, and challenges. Moreover, usage analysis and performance comparisons are investigated in order to derive the suitability of each prediction objective to the various applications. Also, the relevant challenges and open research areas are identified to guide the potential new directions of prediction-based research in VANETs. Throughout this paper, information is provided to developers and researchers to grasp the major contributions and challenges of the predictive protocols in order to pave the way for enhancing their reliability and robustness in VANETs.

7. Conclusion

Due to the highly dynamic topology of VANETs, modeling and predicting the vehicle mobility could play a key role in designing efficient communication protocols. Fortunately, the movements of the vehicles are usually constrained along roads and streets. Therefore, the future movements of the vehicles are predictable. In the literature, numerous predictionbased protocols are proposed to enhance several aspects of VANETs. In this paper, a literature review of prediction-based protocols for VANETs is presented with reference to their application, prediction objective, and performance metrics. Additionally, two novel taxonomies of these protocols are provided. The first one classifies the prediction-based protocols according to the main purpose of the proposed protocols, while the second taxonomy classifies them according to the prediction objective that the proposed protocols aim to predict. A discussion on each category is provided with a focus on the requirements, constrains, and challenges. In order to complement this study, usage analysis and performance comparisons of the prediction-based protocols in VANETs are presented. The analysis derives the suitability of the prediction objectives to the various applications.

In conclusion, predicting the link stability is vital to increase the performance of reactive routing protocols in VANETs, while predicting the future location or trajectory of the vehicles is useful to enhance the position-based routing and data forwarding protocols. Traffic management can be improved by predicting vehicle traveling time, and road safety could take the benefits of predicting the collision risk.