| 摘要: | 無線寬頻技術已被廣泛地應用在無線網際網路存取上。隨著成熟的無線傳輸技術，在應用上一個嶄新的需求與觀念被提出，即是將無線設備結合公車、火車及一般車輛系統上使用。在行車網路服務方面，包含了定位、行車安全資訊、即時多媒體…等服務也逐漸受到重視，例如公車上接收數位廣播電視以及在移動的交通工具上使用網路協助路況資訊的取得。在台灣，每年都有許多因為車輛相撞的交通意外發生。當然發生交通事故有很多不同的因素，但百分之九十導致意外的發生都是車輛機械問題、天候不佳或是不當駕駛行為。而統計這些交通意外，很多都是駕駛開車時不注意路況而導致的。在此子計畫中，我們將藉由無線都會網路 (Wireless Metropolitan Area Networks) 概念設計一個適合傳輸系統使用之穩健的通訊協定。於2005 年11 月，國際電子電機暨工程師協會訂定一個在基地台與使用著之間支援移動與上層換手的寬頻無線網路 ─ IEEE 802.16e。此規格有極大的潛力成為未來無線寬頻存取網路底層通訊標準。因此我們將前瞻地採用此標準通訊協定來當作總計劃中所規劃之多點跳躍車用協定網路 (Multi-hop Vehicular Protocol Networks - MVPNets) 之標準。經仔細研讀此規格後，我們發現 IEEE802.16e 並不全然適合 MVPNet；其潛在的缺點甚至會造成網路中傳輸效能降低以及產生一些訊號死角。因此計畫中的另一項工作便是在IEEE 802.16e上開發我們所提出的多點跳躍車用網路協定。為了實現車輛對車輛通訊與車輛對路邊設備通訊的能力，此協定將設計一高效率車與車間多點跳躍轉送的特性，提供此功能以擴大服務範圍以及增強行車系統之傳送效能。如此，基於IEEE 802.16e 規格，我們所設計支援車與車間多點跳躍轉送之車用通訊網路將提供即時的行車資訊以達到改善交通意外。 ; Wireless Broadband Access technology has been widely used for applications of wireless Internet access. With the matured wireless transmission technology, the new demand on wireless applications is toward the concept of deploying wireless devices on transportation systems such as buses, trains and vehicles. It includes location positioning, traffic safety, entertainment and multimedia for driving network service. The people focus on these services progressively. Every year in Taiwan, about many traffic accidents occur due to automobile crashes. While different factors contribute to vehicle crashes, such as vehicle mechanical problems and bad weather, driver behavior is considered to be the leading cause of more than 90 percent of all accidents. Statistics of car accident cases show that car accidents are often caused from drivers unnoticing road situations during driving. In this sub-project, we will design a robust MAC protocol, which is based on wireless metropolitan area network standard, to fulfill the requirements of transportation system. In November 2005, the IEEE 802.16e working group has approved the standard to support mobility and higher layer handover between base station and subscribers. This standard has the potential to become the MAC and PHY standard in wireless broadband access networks. Therefore, we decide to use this standard protocol as the fundamental transmission protocol in our multi-hop vehicular protocol networks (MVPNets). After we studied the specifications, we found that the IEEE 802.16e has some obviously drawbacks, which will downgrade the transmission performance and bring coverage problem. Therefore, another important goal in this integrated project is to enhance the standard protocol and develop the proposed protocol over the IEEE802.16e. In order to realize vehicle-to-vehicle communications and vehicle-to-roadside capability, the protocol will be allowed to provide specifications for multi-hop relay features, functions and interoperable relaying to extended coverage and system capacity of 802.16e networks. Such the case, we design the multi-hop relaying protocol for vehicular network which can provide real-time vehicular information to avoid traffic problem and accident substantially. ; 研究期間 9708 ~ 9807 |
