行動隨意式網路(Ad Hoc)及寬頻衛星整合之最佳路由擇取研析;+B5202Study of Optimal Routing Scheme in Integrated Mobile Ad Hoc and Satellite Networks

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Title:	行動隨意式網路(Ad Hoc)及寬頻衛星整合之最佳路由擇取研析;+B5202Study of Optimal Routing Scheme in Integrated Mobile Ad Hoc and Satellite Networks
Authors:	吳中實
Contributors:	通訊工程系
Keywords:	電信工程
Date:	2007-12-01
Issue Date:	2010-12-28 15:54:27 (UTC+8)
Publisher:	行政院國家科學委員會
Abstract:	近年來，Ad hoc networks 的路由協定一直被廣泛地討論，然而大多數的Ad hoc networks 路由協定，仍是以最短路徑為基礎的演算法。所以在 Ad hoc networks 中，由於每個傳送者與接收者皆具有行動的機動性。因此對於接收者而言，當其移動超出傳送功率最大範圍時，便會造成兩個行動節點之間的無線連結失敗。倘若在通訊中，發生了連線失敗時，便需花費一段時間，才能偵測到原來的最短路徑已不存在，此時也會造成在傳送中的封包發生遺失的現象。在這個計畫中，我們將研究一個新的路由演算法則，其簡稱為長效存活演算法(Longer Life Routing)，長效存活演算法採用Ad hoc networks 的 Hybrid 模式，利用自身的Global Positioning System(GPS)裝置。來收集Ad hoc networks 中，會以週期性改變位置的其他鄰近行動節點的資訊，而GPS 的資訊，可以預測其它行動節點的速率，以及其所移動的方向。因此行動節點可以估算出，其在無線網路中能存活的時間，每當需要一個新路由路徑時，來源端節點才會區尋找一個長效存活時間的路徑。此外LLR 能夠預測出，在現有的路由路徑即將發生連線中斷時，在此路徑上的所有行動節點，皆會順勢根據現有的路徑，在去找出其它替代的路徑，不過此動作必須在原來路徑發生失敗之前完成。最後，我們將說明LLR 的方法，可以有效遞減低封包傳送的延遲時間，以及比較最短路徑封包的遺失率，將使有限與無線網路頻寬獲得更有效的利用；另一方面，可藉由multi-hop 的技術與衛星通訊，將MVLAN 的範圍拓展到通信基礎設施不足、或因天災導致斷訊的區域，能隨時隨地通訊的資訊網路。 Routing protocols have been widely studied in Ad hoc networks. However, most of the Ad hoc network routing protocols are based on short path algorithms. In Ad hoc networks, due to the mobility of the transmitters or the receivers, a receiver can easily move outside of the power range of its transmitter and this causes the wireless link between the two mobile nodes to fail. When link failure occurs during a communication session, it costs a lot to detect that the shortest routing path is no longer feasible and to retransmit the lost packets. In this project, we propose a new routing algorithm called the Longer Lifetime Routing algorithm(LLR). LLR is a hybrid type of Ad hoc network routing algorithm. Every mobile node in the Ad hoc network periodically exchanges position information collected using Global Positioning System(GPS) devices with other nodes. With the GPS information, the mobile nodes can estimate the velocity and the moving direction of other mobile nodes. Hence, the mobile nodes can estimate the lifetime of the wireless links. When a new routing path is needed, the source node finds the path that has the longest lifetime. Furthermore, LLR can predict when the current routing path will fail due to the mobility of the mobile nodes along the path and find an alternative routing path before the path failure. In summary, we will show that LLR can effectively reduce average packet transmission delay and packet lost rate comparing to shortest path routing algorithm. First, through the MVLAN technique, the transparent handoff of mobile station can be achieved and the network bandwidth can be efficiently and effectively utilized. Second, through the ad hoc networking technique with satellites communication, the VLAN scope can be scaled to include areas where the communication infrastructure is insufficient. 研究期間：9601 ~ 9612
Relation:	財團法人國家實驗研究院科技政策研究與資訊中心
Appears in Collections:	[Department of Communication Engineering] Research Project

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