An Efficient Highway Emergency Broadcast Routing Protocol Based on Stability

[[abstract]]近年來，車載隨意網路是無線隨意網路中相當熱門的研究主題。自從歐美及日本各國已採納IEEE 802.11p以及IEEE 1609系列規範為車載無線網路的主要標準後，其安全性應用在車間通訊中扮演十分重要的角色。然而，在緊急廣播這項安全性應用之中，目前已有許多路由協定紛紛被提出。由於，大部分的方法未能有效的改善隱藏節點及媒體競爭的問題，導致後方的用路人無法收到緊急訊息，或者無法即時收到緊急通知，將有可能造成嚴重的連環車禍。因此，本篇最適轉傳車緊急廣播策略，提出了穩定係數進行轉傳車輛篩選，以傳輸範圍內最穩定的車輛進行傳輸，確保事故車後方所有車輛都能成功接收緊急訊息，避免二次事故的發生。接著再追求低延遲的緊急訊息傳輸，讓後方用路人能夠快速收到通知，進而提早做出適當的反應。此外，所提出的方法以NS2來模擬車用無線短程通訊技術，並進行了穩定係數分析。由實驗結果可以得知，所提出的方法，無論是在任何場景下的接收率，以及傳輸上的延遲時間，相較其他路由協定，皆有相當不錯的表現。[[abstract]]In recent year, Vehicular Ad hoc Network (VANET) is a significant research topic in Ad hoc Network. Since IEEE 802.11p and IEEE 1609 standards have been adopted as the main technology in US, EU and JP, vehicular safety application has played an important role in VANETs. There are many emergency broadcast protocols had been proposed, but most of these schemes could not improve hidden terminal and intense media contention problems efficiently. These problems will lead to rear drivers could not successfully receive emergency messages in time, and finally causes a serious chain reaction accident. Therefore, to make sure each vehicle can receive emergency packets, and avoiding the second accident. The proposed protocol called Appropriate Vehicular Emergency Dissemination (AVED), using stability to select the most stable forwarder in the transmission range to relay the emergency packet. After that, to allow rear drivers to take appropriate response, emergency messages must be quickly forwarded to shorten the latency. In addition, the proposed method is implemented with NS2 simulator based on WAVE/DSRC standard and having analysis of stability. The simulation results show that the proposed protocol has outstanding reception rate and delay time in any different highway environment.[[note]]碩