車載通訊網路可增加道路安全性並提供車輛存取網際網路的豐富資源。基於成本考量，在路側系統無法全面覆蓋的環境中，車輛可透過多步傳輸的方式存取路側系統資源。然而，如何提昇其頻寬使用效能、維護資料存取的公平性以及避免封包衝撞，仍是急待解決的問題。本論文將針對道路環境下發展一車輛存取網路的MAC技術，我們所提出的方法主要是在TDMA及道路分段的環境下，以維持車輛存取網路之公平性為主旨及提昇頻寬利用率為目的，針對不同的道路片段間，其車輛數可能不同的情況，加以考慮，以分散式的方式，達到車輛間存取頻寬的公平性。 Vehicular Ad Hoc Networks (VANETs) technologies can improve traffic safety for drivers and provide comfort services for passengers. Since the hardware of Road Side Unit (RSU) is costly, in most previous researches, vehicles might exchange data with an RSU via multihop transmissions. However, the vehicle with a larger number of hops to the RSU has fewer opportunities and longer time to exchange its data with the RSU since the contentions and collisions increase with the number of hops. Moreover, for high bandwidth utilization, the fairness of vehicles may be sacrificed. This paper proposes a Fairness Enhanced MAC protocol, named Fair-MAC which considers a vehicular ad hoc network that accesses the Internet through fixed Internet Gateways along the road. The Fair-MAC aims to increase fairness, maintain bandwidth utilization, and avoid collision. The performance study reveals that the proposed MAC protocol not only avoids the collision problem but also improves the performance in terms of end-to-end throughput and fairness.
