提升存活時間之適應性隨意行動無線網路擇路協定

Abstract

隨意行動無線網路是由一種不需要經由基礎建設的設備所形成的網路。在隨意無線網路中的行動節點可以在彼此之間做封包交換。由於目前的擇路演算法只考慮到中繼節點的數量多寡，而忽略到電池能量限制與移動模式等的影響。在考慮網路存活時間情況下，這篇論文將介紹提升存活時間之適應性擇路演算法（Lifetime-Enhanced Adaptive Routing Protocol，LEAR），當擇路表單內有多條到目的節點的路徑時，資料的傳送可以選擇避開能量不足的中繼節點，提供單一多路徑資料傳輸的可靠性。當行動運算節點的能量低於設定臨界值時，會發送一個低能量通知的控制封包給上一個傳送資料的行動節點。當行動運算節的收到此控制封包，會更新擇路路表單的剩餘路徑能量，透過此機制以提升整個網路的存活時間及減少行動節點電池耗盡的數量。

The mobile nodes (MNs) in the Mobile Ad hoc NETwork (MANET) can exchange their data packets directly without the existence of network infrastructure. In recent research work, hop counts within the transmission route are considered for routing decision. However, the influence from the receiving power and remaining energy of the MNs are not fully investigated. This may results in degraded network lifetime within the MANET to successfully transmit the data packets. In this thesis, a Lifetime-Enhanced Adaptive Routing (LEAR) protocol is proposed for unicast multipath routing of data packets. As there are more than two routing paths existed within the routing table, the proposed LEAR algorithm will avoid adopting the low-energy intermediate node in the decision of the transmitting path. The reliability for packet transmission can therefore be preserved. When the remaining energy of the intermediate MN is less than a predetermined threshold, a control packet will be delivered to its previous hop node for noticing the status of low energy. The routing path will therefore be reselected based on the updated energy status. From the simulation results, it can be observed that the proposed LEAR protocol increases the network life-time by reducing the total number of death nodes within the network topology.